in the present invention , venous blood denotes blood that has bled from a blood vessel of a patient through a cannula , and cardiotomy blood denotes blood ( vented blood or suction blood ) that is withdrawn from outside or inside the heart in the surgical field ( the field of operation ). furthermore , foreign material in the present invention denotes a substance other than blood that has the possibility of inclusion in cardiotomy blood such as fat globule , soft - tissue fragments , bone fragments , denatured protein , platelet clump , or the like . fig1 is an external view of a blood reservoir 1 according to a first embodiment of the present invention . fig2 is a partial perspective view of a second support member 22 in a filter support unit 20 . fig3 is a perspective view of a filter retaining member 222 that configures the second support member 22 . fig4 is a perspective view of a bottom member 322 that configures the second support member 22 . fig5 is a sectional view of the blood reservoir 1 . fig6 and fig7 are side views of the second cardiotomy blood filter member 52 before mounting . fig8 is a view illustrating the relationship between the angle of inclination of the guide member and the density of the material configuring the guide member 60 . the blood reservoir 1 includes a housing 10 , a filter support unit 20 , a blood guiding pipe 30 , a venous blood filter means 40 , a cardiotomy blood filter means 50 , and a guide member 60 . as shown in fig1 , the housing 10 includes a housing main body 11 and a cover 12 . as shown in fig5 , a storage space s that stores blood is formed in the housing 10 . the storage space s is a space inside the housing 10 that is formed by mounting the cover 12 onto the housing main body 11 . the housing main body 11 forms a box shape in which a portion has an opened configuration . the opening in the housing main body 11 is formed substantially in an oval shape , or substantially in a quadrilateral shape . as shown fig1 and fig5 , the housing main body 11 includes a box portion 11 a and a protruding portion lib . the box portion 11 a forms the storage space s on the blood inflow side , that is to say , forms an upper storage space sa . the protruding portion 11 b forms the storage space s on the blood outflow side , that is to say , forms a lower storage space sb . the protruding portion 11 b is a portion of the bottom portion of the box portion 11 a that projects outwardly , and is integrally formed with the box portion 11 a . a pipe - shaped blood outflow port 11 c communicating from the storage space s to the outside is provided on the bottom portion of the protruding portion 11 b . for example the blood outflow port 11 c is connected to a tube of the blood line in the external blood recirculation path . as used herein , one side face of the box portion 11 a and one face of the protruding portion 11 b are formed on the same surface . a scale ( not shown ) is provided on the above surface to confirm the blood storage amount . the bottom portion of the box portion 11 a and the bottom portion of the protruding portion 11 b face the opening of the housing main body 11 . as shown in fig1 and fig5 , the cover 12 is fitted and mounted on the housing main body 11 to cover the opening of the housing main body 11 . a first blood input port 12 a and a second blood inflow port 12 b are provided in the cover 12 . the first blood input port 12 a for example is connected to a tube of a blood extraction line for venous blood in the external blood recirculation path . the second blood input port 12 b for example is connected to a tube of the cardiotomy blood line in the external blood recirculation path . the first blood input port 12 a and the second blood inflow port 12 b communicate from an external portion to the storage space s , for example , the upper storage space sa when the cover 12 is mounted on the housing main body 11 . an air bleed port ( not shown ) allowing entry and exit of air depending on fluctuation in the amount of blood in the blood reservoir 1 is provided in the cover 12 . air after defoaming or air after foam breaking is discharged to the outside from the air bleed port . the constituent material used in the housing main body 11 and the cover 12 is for example polycarbonate , acrylic resin , polystyrene , polyvinyl chloride , or the like . the housing main body 11 formed from such a material is preferably substantially transparent in order to enable visual confirmation of the blood storage amount stored in an inner portion of the blood reservoir 1 , and the state of the blood in the inner portion . the filter support unit 20 supports the venous blood filter means 40 and the cardiotomy blood filter means 50 , and is mounted on the housing 10 , for example , on the cover 12 . as shown in fig2 to fig5 , the filter support unit 20 is configured from a first support member 21 and a second support member 22 . the first support member 21 supports the venous blood filter means 40 , for example , the venous blood filter member 41 as described hereafter . the first support member 21 has a frame structure , and is mounted onto the inner surface of the cover 12 . as shown in fig2 to fig5 , the second support member 22 supports the cardiotomy blood filter means 50 , for example , the first cardiotomy blood filter member 51 and the second cardiotomy blood filter member 52 as described hereafter . the second support member 22 is mounted onto the inner surface of the cover 12 . more specifically , the second support member 22 includes a frame 122 , a filter retaining member 222 that retains the second cardiotomy blood filter member 52 with the frame 122 , and a bottom member 322 that supports the bottom portion of the second cardiotomy blood filter member 52 . the frame 122 is mounted onto the inner surface of the cover 12 . the frame 122 includes two opposed plate portions 122 a , a connecting member 122 b connecting the two plate portions 122 a , and a mesh portion 122 c formed on an inner face of each plate portion 122 a . the second support member 22 is mounted on the inner surface of the cover 12 in the two plate portions 122 a . the second cardiotomy blood filter member 52 covers the plate portion 122 a and the connecting member 122 b . the second cardiotomy blood filter member 52 engages the plate portion 122 a and is mounted onto the plate portion 122 a . the filter retaining member 222 is mounted on the inner surface of the cover 12 . the filter retaining member 222 is formed in a box shape along the outer shape of the frame 122 . an opening is formed on the upper portion , the central portion and the lower portion of the filter retaining member 222 . the upper portion of the opening 222 a is a portion for inserting the frame 122 . the central opening 222 b is a through hole . the through hole is a passage of blood that has passed through a first filter portion 52 a of the second cardiotomy blood filter member 52 , for example , a non - woven fabric . the lower opening 222 c is a through hole . the through hole is a passage of blood that has passed through a second filter portion 52 b of the second cardiotomy blood filter member 52 , for example , a mesh fabric ( screen mesh ). the filter retaining member 222 is mounted on the cover 12 with the second cardiotomy blood filter member 52 covered by the frame 122 . the bottom member 322 is mounted on the filter retaining member 222 . more specifically , the bottom member 322 is mounted on the opening 222 c formed in the filter retaining member 222 . the bottom member 322 is formed to enable passage of cardiotomy blood into an inner portion in a supported configuration . in the supported configuration , the bottom member 322 supports the bottom portion ( the second filter portion 52 b described below ) of the second cardiotomy blood filter member 52 . the bottom member 322 is formed from a support portion 322 a that supports the bottom portion of the second cardiotomy blood filter member 52 , and a passage 322 b that enables passage of cardiotomy blood from the cardiotomy blood filter means 50 . the support portion 322 a is formed in a plate shape , and is placed in abutment with the bottom portion of the second cardiotomy blood filter member 52 to thereby support the bottom portion of the second cardiotomy blood filter member 52 . the passage 322 b is formed as a rectangular tube . in other words , the passage 322 b is formed as a hollow beak shape . the opening 322 c is provided on the opposed side face on the passage 322 b . in this manner , cardiotomy blood that passes through the passage 322 b flows out from the opening 322 c in addition to the distal tip of the passage 322 b . furthermore , when the bottom member 322 is mounted on the filter retaining member 222 , the passage 322 b is set to a predetermined angle of inclination a with reference to the horizontal plane ( refer to fig5 ). more specifically , the bottom member 322 is mounted on the filter retaining member 222 so that the angle of inclination α of the passage 322 b relative to the horizontal plane is approximately 65 degrees . furthermore , when the bottom member 322 is mounted on the filter retaining member 222 , the distal tip of the passage 322 b of the bottom member 322 is disposed on an inner portion of the protruding portion 11 b . in this manner , cardiotomy blood after filtering is guided from the upper portion of the protruding portion 1 lb into an inner portion of the protruding portion 11 b . the statement “ a inner surface of the cover 12 ” as used herein means the surface opposite the side on which the first blood input port 12 a and the second blood input port 12 b are mounted on the cover 12 . furthermore , the statement “ the top surface of the cover 12 ” as used herein means the surface opposite the inner surface of the cover 12 . in other words , “ the top surface of the cover 12 ” means the surface on the side on which the first blood input port 12 a and the second blood input port 12 b are mounted on the cover 12 . the blood guiding pipe 30 includes a venous blood guiding pipe 31 for guiding venous blood from the first blood input port 12 a into an inner potion the housing 10 , and a cardiotomy blood guiding pipe 32 for guiding cardiotomy blood from the second blood input port 12 b into the housing 10 . the venous blood guiding pipe 31 is mounted on the inner surface of the cover 12 at the position of the first blood input port 12 a . the venous blood guiding pipe 31 is formed as a pipe , and is inserted into an inner portion of the frame structure of the first support member 21 . when the cover 12 is mounted on the housing main body 11 , one end of the venous blood guiding pipe 31 is mounted onto the inner surface of the cover 12 , and the other end is positioned in an inner portion of the protruding portion 11 b . in other words , when the cover 12 is mounted on the housing main body 11 , the venous blood guiding pipe 31 is disposed in the housing 10 extending from the first blood input port 12 a of the cover 12 in an inclined configuration towards the protruding portion 11 b of the housing main body 11 . the cardiotomy blood guiding pipe 32 is mounted on the inner surface of the cover 12 at the position of the second blood input port 12 b . more specifically , the cardiotomy blood guiding pipe 32 is formed as a pipe , and is mounted on the inner surface of the cover 12 at the position of the second blood input port 12 b between the second support member 22 and the cover 12 . when the cover 12 is mounted on the housing main body 11 , one end of the cardiotomy blood guiding pipe 32 is mounted onto the inner surface of the cover 12 , and the other end is located above the protruding portion 11 b . in other words , when the cover 12 is mounted on the housing main body 11 , the cardiotomy blood guiding pipe 32 is disposed in the second support member 22 , for example , in an inner portion of the frame 122 with extending from the second blood input port 12 b of the cover 12 downwards towards the protruding portion 11 b of the housing main body 11 . although an example is described herein in which the cardiotomy blood guiding pipe 32 is mounted on the inner surface of the cover 12 at the position of the second blood input port 12 b , the cardiotomy blood guiding pipe 32 may be integrally formed with the inner surface of the cover 12 at the position of the second blood input port 12 b . the venous blood filter means 40 is mounted in the housing 10 . the venous blood filter means 40 includes a venous blood filter member 41 . the venous blood filter member 41 removes bubbles from venous blood guided from the first blood input port 12 a through the venous blood guide pipe 31 into the housing 10 . for this reason , it is preferred that the hole diameter of the venous blood filter member 41 is approximately 20 - 40 μm . the venous blood filter member 41 is formed as a bag with a portion thereof in an opened configuration , and is disposed in the housing 10 . more specifically , the venous blood filter member 41 is formed as a bag with an upper portion thereof in an opened configuration , and is mounted on an outer surface of the first support member 21 of the filter support unit 20 . still more specifically , the venous blood filter member 41 is mounted on the first support member 21 of the filter support unit 20 to enclose the frame structure of the first support member 21 of the filter support unit 20 . in this manner , when the cover 12 is mounted on the housing main body 11 , the venous blood filter member 41 is disposed in the housing 10 to extend from the first blood inflow port 12 a of the cover 12 inclining towards the protruding portion 11 b of the housing main body 11 . the cardiotomy blood filter means 50 is mounted in the housing 10 . the cardiotomy blood filter means 50 includes the first cardiotomy blood filter member 51 and the second cardiotomy blood filter member 52 . the first cardiotomy blood filter member 51 removes relatively large foreign matter and bubbles from cardiotomy blood guided from the second blood inflow port 12 b through the cardiotomy blood guide pipe 32 to the inner portion of the housing 10 . the first cardiotomy blood filter member 51 is formed in a hat shape with a portion thereof in an opened configuration , and is disposed in the housing 10 . the first cardiotomy blood filter member 51 is mounted onto the inner surface of the cover 12 . more specifically , the first cardiotomy blood filter member 51 includes a flange portion 51 a and an concave portion 51 b . still more specifically , the concave portion 51 b of the first cardiotomy blood filter member 51 is fitted to the cardiotomy blood guide pipe 32 , and the flange portion 51 a is mounted on the inner surface of the cover 12 . the flange portion 51 a of the first cardiotomy blood filter member 51 is supported by the second support member 22 mounted on the cover 12 . more specifically , the flange portion 51 a of the first cardiotomy blood filter member 51 is supported by a claw portion 122 c provided on the frame 122 of the second support member 22 . foam urethane is used in the first cardiotomy blood filter member 51 . a defoaming agent , such as silicone that defoams bubbles when coming into contact with bubbles , is coated on an inner surface of the first cardiotomy blood filter member 51 , for example , on the inner surface of the concave portion 51 b . for that reason , when the cardiotomy blood comes into contact with the inner surface of the first filter member 51 before cardiotomy blood passing through the first cardiotomy blood filter member 51 , the bubbles contained in the cardiotomy blood are burst by the defoaming agent . after the cardiotomy blood passes through the first cardiotomy blood filter member 51 , bubbles of more than a predetermined size corresponding to the size of the cavities in the first cardiotomy blood filter member 51 are removed from the cardiotomy blood . furthermore , when the cardiotomy blood passes through the first cardiotomy blood filter member 51 , foreign matter is also removed from the cardiotomy blood . for example , foreign matter having a size that is larger than the cavities of the first cardiotomy blood filter member 51 is removed from the cardiotomy blood . the second cardiotomy blood filter member 52 removes foreign matter and bubbles from cardiotomy blood that has passed through the first filter member , that is to say , from cardiotomy blood from which relatively large foreign matter and bubbles have been removed by the second cardiotomy blood filter member 52 . it is preferred that the hole diameter of the second cardiotomy blood filter member 52 is approximately 20 - 200 μm . the second cardiotomy blood filter member 52 is formed as a bag with a portion thereof in an opened configuration , and is disposed in the housing 10 . more specifically , the second cardiotomy blood filter member 52 is formed as a bag with an upper portion thereof in an opened configuration . in addition , the second cardiotomy blood filter member 52 is mounted on the second support member 22 of the filter support unit 20 that is disposed on an outer side of the first cardiotomy blood filter member 51 . for example , the second cardiotomy blood filter member 52 is covered by the plate portion 122 a and the connecting member 122 b , and is engaged and mounted on the plate portion 122 a . in this configuration , the filter retaining member 222 is mounted on the frame 122 . the bottom member 322 is mounted in the through hole 222 c that is formed in the filter retaining member 222 . in this manner , the second cardiotomy blood filter member 52 is supported on the filter support unit 20 with the bottom portion folded inwardly . furthermore in this configuration , the first cardiotomy blood filter member 51 is disposed on an inner portion of the second cardiotomy blood filter member 52 . more specifically , as shown in fig6 and fig7 , the second cardiotomy blood filter member 52 includes the first filter portion 52 a and the second filter portion 52 b . the first filter portion 52 a forms a wall portion in the bag - shaped second cardiotomy blood filter member 52 , that is to say , an upstream wall portion on a upstream side in the direction of the inflow of blood . the first filter portion 52 a is configured from a two substantially trapezoid sheet - shaped mesh members . more specifically , the first filter portion 52 a is formed by press fitting or welding the two side edges ( the edges excluding the upper edge and the lower edge ) of the two mesh members . the first filter portion 52 a is formed for example from non - woven fabric . the first filter portion 52 a is mounted on the frame 122 on the edge forming the upper opening . the statement “ substantially trapezoid ” as used herein means a “ trapezoid having a lower edge that projects outwardly ”, or “ a trapezoid that has a lower edge that bends outwardly ”. the second filter portion 52 b forms a bottom portion on a downstream side in the direction of the inflow of blood . the second filter portion 52 b is configured from a two substantially trapezoid sheet - shaped mesh members . more specifically , the substantially trapezoid sheet - shaped mesh members 52 b for the second filter portion are formed so that the height h 2 ( height of the trapezoid ) of the substantially trapezoid sheet - shaped mesh members 52 b for the second filter portion is smaller than the height h 1 ( height of the trapezoid ) of the substantially trapezoid sheet - shaped mesh members 52 a for the first filter portion . more specifically , the substantially trapezoid sheet - shaped mesh members 52 b for the second filter portion are preferably formed so that the height h 2 of the substantially trapezoid sheet - shaped mesh members 52 b for the second filter portion is approximately ⅓ of the height h 1 of the substantially trapezoid sheet - shaped mesh members 52 a for the first filter portion . the two side edges ( the edges excluding the upper edge and the lower edge ) of the two mesh members are press fitted or welded to thereby form the second filter portion 52 b . the lower edge of the second filter portion 52 b ( the respective lower edges of the two mesh members that configure the second filter portion 52 b ) are press fitted or welded to the upper edge ( the respective upper edges of the two mesh members that configure the first filter portion 52 a ) to thereby form the second cardiotomy blood filter member 52 ( refer to fig6 ). in this configuration , the second filter portion 52 b is supported on the bottom member 322 , and is formed into a projecting shape on an upstream side with reference to the inflow of blood ( refer to fig5 ). when the second cardiotomy blood filter member 52 is disposed between the frame 122 and the filter retaining member 222 , and the bottom member 322 is mounted onto the lower portion of the filter retaining member 222 , the second filter portion 52 b is folded towards an inner surface of the first filter portion 52 a on the connecting member 52 c ( press fitted portion or welded portion ) with the first filter portion 52 a ( refer to fig5 and fig7 ). consequently , the second filter portion 52 b is supported on the support portion 322 a of the bottom member 322 . thus , the second filter portion 52 b is maintained in a projecting shape on the upstream side in the direction of the inflow of blood in the housing 10 . in this configuration , when cardiotomy blood passes through the second filter portion 52 b , the cardiotomy blood passes through the passage 322 b of the bottom member 322 . the second filter portion 52 b has a different specification from the first filter portion 52 a . for example , the second filter portion 52 b is formed from a material that has higher liquid permeation characteristics than the first filter portion 52 a . more specifically , the second filter portion 52 b is formed from a mesh fabric ( screen mesh ). the term “ specification ” as used herein includes at least any one of structure , material , property , or the like . herein , an example of the term “ specification ” in relation to structure will be described . when the cardiotomy blood passes through the second cardiotomy blood filter member 52 , foreign matter that could not be removed by the first cardiotomy blood filter member 51 is removed . furthermore , at this time , bubbles that could not be removed by the first cardiotomy blood filter member 51 are removed from the cardiotomy blood . in other words , foreign matter and bubbles of a predetermined size that corresponds to the size of the cavities ( minute holes ) of the second cardiotomy blood filter member 52 are removed from the cardiotomy blood . for example , foreign matter and bubbles of at least 40 microns are removed from the cardiotomy blood as a result of the cardiotomy blood passing through the second cardiotomy blood filter member 52 . as shown in fig5 , the guide member 60 is disposed between the cardiotomy blood filter means 50 and the blood outflow port 11 c , and is a member that guides the blood that has been filtered by the cardiotomy blood filter means 50 towards the blood outflow port 11 c . more specifically , as shown in fig4 , the guide member 60 is mounted on the second support member 22 , that is to say , on the bottom member 322 . still more specifically , the guide member 60 is formed in a plate shape , and is inserted and mounted in an inner portion of the passage 322 b of the bottom member 322 . the guide member 60 is configured from a foam material compressed with respect to a direction of thickness . a material is used in the guide member 60 , the material has a density d that corresponds to the angle of inclination α of the bottom member 322 , for example , that corresponds to the angle of inclination α of the passage 322 b of the bottom member 322 . for example , the guide member 60 is configured from a material that has a density d within a range of 0 . 12 g / cm 3 to 0 . 16 g / cm 3 . in this example , the guide member 60 is configured from a material that , has a density d of 0 . 13 g / cm 3 . foam urethane for example is used in the guide member 60 . more specifically , compressed foam urethane in which foam urethane has been compressed is used in the guide member 60 . the compressed foam urethane used in this example is a foam urethane having a thickness of 2 mm that is formed by compressing a foam urethane having a thickness of 10 mm . for example , when commercially available foam urethane having a density of 26 - 30 kg / m 3 is compressed in the above manner , compressed foam urethane with a density of 0 . 13 to 0 . 15 g / cm 3 is obtained . generally , the spaces in the guide member 60 are reduced in size as the density d in the material configuring the guide member 60 increases . as a result , permeation of blood into the guide member 60 is hindered as a result of an increase in the density d of the material in the guide member 60 . in other words , when the density d of the material in the guide member 60 increases , blood tends to flow across the surface of the guide member 60 without permeating the guide member 60 . as a result , when the density d of the material in the guide member 60 increases , the speed of flow of blood through the guide member 60 tends to increase . due to this reason , for example , it is desirable to dispose the guide member 60 so that the angle of inclination α of the guide member 60 is reduced as the density d of the material in the guide member 60 increases . fig5 shows an example in which the density d of the material in the guide member 60 is 0 . 13 g / cm 3 . however , due to the above reasons , when the angle of inclination a of the bottom member 322 is varied , it is desirable to vary the density d of the material . as shown in fig8 , when the angle of inclination α is 70 degrees and over , it is desirable to use a porous material with a density d in the range of 0 . 02 g / cm 3 to 0 . 05 g / cm 3 . furthermore , when the angle of inclination α is at least 65 degrees and less than 70 degrees , it is desirable to use a porous material with a density din the range of 0 . 05 g / cm 3 to 0 . 20 g / cm 3 . yet furthermore , when the angle of inclination α is less than 65 degrees , it is desirable to use a porous material with a density d in the range of 0 . 20 g / cm 3 to 0 . 40 g / cm 3 . the blood storage features of the blood reservoir 1 will be described below . when venous blood reaches the blood inflow port , that is to say , the first blood inflow portion 12 a , connected to the tube on the blood - extraction line for venous blood in the external blood recirculation path , the venous blood is guided into the housing 10 through the venous blood guide pipe 31 . since the distal end of the venous blood guide pipe 31 ( referred to above as the other end ) extends into an inner portion of the protruding portion 11 b of the housing 10 , the venous blood is guided into proximity with the bottom portion of the venous blood filter portion member 41 . in this manner , the venous blood commences to accumulate from the bottom portion upwardly in the inner portion of the venous blood filter member 41 . thus , when the venous blood passes through the venous blood filter member 41 , bubbles contained in the venous blood are defoamed by the member 41 . in this manner , the venous blood is filtered by the venous blood filter member 41 , that is to say , by the venous blood filter means 40 , and is stored in the blood reservoir 1 . when venous blood reaches the blood inflow port , that is to say , the second blood inflow portion 12 b , connected to the tube on the blood - extraction line for cardiotomy blood in the external blood recirculation path , the cardiotomy blood is guided into the housing 10 through the cardiotomy blood guide pipe 32 . in this manner , the cardiotomy blood commences to accumulate in the first cardiotomy blood filter member 51 . thus , when the cardiotomy blood passes through the first cardiotomy blood filter member 51 , relatively large foreign matter contained in the cardiotomy blood , for example , bone fragments , soft tissue fragments , and the like , are removed by this filter member . furthermore , when the cardiotomy blood passes through the first cardiotomy blood filter member 51 , relative large bubbles contained in the cardiotomy blood are defoamed or broken by the filter member . in this manner , cardiotomy blood passing through the first cardiotomy blood filter member 51 starts to accumulate in the second cardiotomy blood filter member 52 . when the cardiotomy blood passes through the second cardiotomy blood filter member 52 , foreign matter contained in the cardiotomy blood is removed by the second cardiotomy blood filter member 52 . furthermore , when the cardiotomy blood passes through the second cardiotomy blood filter member 52 , bubbles contained in the cardiotomy blood are defoamed by this filter member . more specifically , when the cardiotomy blood that has passed through the first cardiotomy blood filter member 51 commences to accumulate in the second cardiotomy blood filter member 52 , firstly foreign matter and bubbles contained in the cardiotomy blood are removed by the mesh fabric ( first filter portion 52 a ) of the second cardiotomy blood filter member 52 . then , when the blood processing capacity of the mesh fabric is reduced by blocking or the like , foreign matter and bubbles contained in the cardiotomy blood are removed by the non - woven fabric ( second filter portion 52 b ) of the second cardiotomy blood filter member 52 . in this manner , the cardiotomy blood is filtered by the first cardiotomy blood filter member 51 and the second cardiotomy blood filter member 52 , that is to say , by the cardiotomy blood filter means 50 . in this manner , the blood that has been filtered by the cardiotomy blood filter means 50 is guided towards the blood outflow port 11 c by the guide member 60 . more specifically , the blood guided by the guide member 60 accumulates in the protruding portion 11 b of the housing 10 . in this manner , the cardiotomy blood is filtered by the cardiotomy blood filter means 50 , and accumulated in the lower storage space sb of the blood reservoir 1 . the characteristics of the blood reservoir 1 will be described below . in the present embodiment , the cardiotomy blood filter means 50 includes the second cardiotomy blood filter member 52 . in the second cardiotomy blood filter member 52 , the bottom portion ( second filter portion 52 b ) is formed as a projecting shape with respect to the upstream side in the direction of blood inflow . in this manner , the blood processing capacity in the filter member can be improved . [ 0099 ] furthermore the second cardiotomy blood filter member 52 can be easily processed and manufactured by connection to the wall portion so that the bottom portion ( second filter portion 52 b ) in the second cardiotomy blood filter member 52 can be folded inwardly towards the wall portion ( first filter portion 52 a ) in the second cardiotomy blood filter member 52 . in addition , the wall portion ( first filter portion 52 a ) in the second cardiotomy blood filter member 52 is formed from a non - woven fabric . furthermore , the bottom portion ( second filter portion 52 b ) in the second cardiotomy blood filter member 52 is formed from mesh fabric . consequently , when blood starts to flow into the inner portion of the second filter member , the blood mainly passes through the mesh fabric ( bottom portion ). then when the blood processing capacity of the mesh fabric is reduced by blocking or the like , the blood starts to pass through the non - woven fabric ( wall portion ). in this manner , when the blood is mainly passing through the mesh fabric , foreign matter and bubbles can be removed from the blood at a high speed . thereafter , when the blood is mainly passing through the non - woven fabric , although the blood processing capacity of the mesh fabric is reduced , foreign matter and bubbles can be stably removed from the blood . in the present embodiment , the blood reservoir 1 includes the cardiotomy blood filter means 50 . the cardiotomy blood filter means 50 includes the second cardiotomy blood filter member 52 . thus the blood reservoir 1 according to the present embodiment obtains the same effect as the effect of the second cardiotomy blood filter member 52 . in this manner , medical personnel who manage the blood reservoir 1 can more accurately comprehend the blood storage amount accumulated in the blood reservoir 1 . ( a ) in the above embodiment , although an example was described in which cardiotomy blood was filtered by the cardiotomy blood filter means 50 in the blood reservoir 1 , the feature of filtering cardiotomy blood is not limited thereby , and may take any configuration . for example , the cardiotomy blood filter means 50 may be separated , and a cardiotomy reservoir may be additionally provided . the cardiotomy blood filter means 50 may be provided in such a cardiotomy reservoir . in this configuration , venous blood is filtered in the filter means ( venous blood filter means 40 ) of the blood reservoir , and cardiotomy blood is filtered in the filter means ( cardiotomy blood filter means 50 ) of the cardiotomy reservoir . in this manner , the same effect as the above embodiment is obtained even when blood is filtered in the blood reservoir 1 and the cardiotomy reservoir . use is possible in relation to a blood reservoir for storing venous blood and / or cardiotomy blood .
provided is a blood storage tank equipped with a filter having a treatment capacity desired by a health worker . a health worker managing a blood storage tank can comprehend the amount of stored blood more accurately . furthermore , bubbles are prevented from being mixed into blood after bubbles are removed therefrom . a filter member of a blood storage tank is a filter member for removing foreign matters and bubbles from the blood . the filter member is equipped with a first filter portion and a second filter portion . the first filter portion forms the wall portion and the second filter portion forms the bottom portion . specifications of the first filter portion and the second filter portion are different . the guide member of the blood storage tank consists of foaming material . the blood from which bubbles are removed are thereby led in a state where the blood permeated the guide member . consequently , the guide member can lead the blood from which bubbles are removed to a predetermined position at an appropriate landing speed .