JPH0111249Y2 - - Google Patents

Description

[Detailed Description of the Invention] Background of the Invention [Technical Field] The present invention relates to a blood heat exchanger used to maintain, cool, or rewarm a patient's blood at a constant temperature during surgery or the like. [Prior Art] A blood heat exchanger is used to bring blood taken out from the human body to a predetermined temperature and then supply it back into the body, and is used, for example, in an extracorporeal circulation circuit of an artificial lung. A multi-tubular blood heat exchanger is, for example, a tube body installed in a blood flow tank for blood taken out from the body, through which a heat exchange medium such as cooling water or hot water can pass. There are some that pass along multiple tube bodies. That is, this blood heat exchanger includes a blood inlet that allows blood taken out from the body to flow into the blood flow tank, and a blood outlet that allows blood that has passed through the blood flow tank to be supplied to the inside of the body. It becomes. The blood flowing into the blood flow tank undergoes heat exchange as it passes between the plurality of tubes disposed between the blood inlet and the blood outlet in the blood flow tank. The exchanged blood flows out from the blood outlet and is supplied to the inside of the body. By the way, in the conventional multi-tube blood heat exchanger that allows blood to flow along the tubes as described above, the flow rate of blood passing around the plurality of tubes differs in the vicinity of each tube. . In other words, since blood in the blood flow tank tends to flow in a short-circuited manner along a straight line from the blood inlet to the blood outlet, there is a substantially straight line position connecting the blood inlet and blood outlet in the blood flow tank. There is a problem in that the flow rate of blood passing through a portion of the tube body disposed above is too high, and the flow rate of blood passing through a portion of the tube body disposed at a position deviating from the linear position is too low. For this reason, it is not possible to exchange heat evenly with all the blood passing through the tube, and there is also the problem that the temperature distribution of the blood passing through differs at each tube body position, resulting in localized heat exchange of blood being too much or too little. There is a risk of adverse effects on blood components. Conventionally, in order to perform sufficient heat exchange, heat exchangers have been made large, or baffles have been placed at each of the blood inlet and blood outlet in the blood flow tank, and multiple tube bodies for heat exchange have been used. A blood heat exchanger has been proposed in which the flow rate of blood passing through each blood is kept constant. According to this heat exchanger, all the tubes can contribute to heat exchange, and uniform heat exchange of the blood passing through the tube becomes possible. However, when a baffle plate is provided at each of the blood inlet and blood outlet, the blood flowing into or out of the blood flow tank collides with the baffle plate or the inner wall of the blood flow tank. Therefore, blood cells, platelets, etc. in the blood components may be destroyed by the collision, causing blood damage. Furthermore, the resistance to blood flowing into the heat exchanger increases, increasing the burden on blood pumps and the like. Purpose of the invention The purpose of the invention is to enable uniform heat exchange of all blood passing through a blood flow tank using a heat exchanger that can be made small and causes little blood damage. Composition of the Device The present invention includes a blood flow tank having a blood inlet at the bottom and a blood outlet at the top, and a blood flow that crosses the blood flow flowing from the blood inlet to the blood outlet within the blood flow tank. At the same time, a tube group consisting of a plurality of tubes arranged in parallel with each other and extending to the outside of the blood flow tank to allow a heat exchange medium to pass therethrough, and an inlet for the heat exchange medium that communicates with both ends of each tube. and an outlet,
Spaces forming blood flow adjustment chambers are provided below and above approximately the entire area of the tube group installation area in the blood flow tank, and each of the blood flow adjustment chambers is provided so as to correspond to each of the blood inflow port and blood outflow port. It is designed to open on the side of the chamber. Further, in the present invention, the length of each tube in the blood flow tank is a, the length of the tube group along the blood passage direction in a cross section perpendicular to the longitudinal direction of the tube group is b, and When the width of the tube group in the direction orthogonal to the blood passage direction in the above cross section is c, the ratio of b/a is in the range of 0.7 to 1.5, and c/
The ratio of a is set in the range of 0.5 to 1.0. Effects of the invention According to the invention as set forth in claim 1, there are the following effects. The blood inlet opening into the blood flow tank is located on the side surface of the space of the blood flow adjustment chamber located below substantially the entire area of the tube group installation area. Therefore, the blood that flows in from the blood inflow port first spreads to spread throughout the entire space of the lower blood flow adjustment chamber, and then rises to substantially the entire area of the tube group installation area. This will form a flow. Furthermore, a space for a blood flow adjustment chamber located above substantially the entire area of the tube group installation area is formed in the portion of the blood flow tank where the blood outflow port opens.
Therefore, the blood rising in substantially the entire area of the tube group installation area as described above is allowed to rise without forming a large back pressure resistance in substantially the entire area on the upper blood flow adjustment chamber side. The blood flows into the entire space of the blood flow adjustment chamber, and then flows out to the outside through the blood outflow port opened on the side surface of the blood flow adjustment chamber. Therefore, due to the above, the blood passing through the blood flow tank does not travel in a straight line from the blood inlet to the blood outlet as in the past, but is distributed evenly over the entire area where the tube group is installed. disperse and move. This prevents the flow rate of blood from becoming too much or too little locally in both areas where the tube group is installed, allowing all blood to exchange heat evenly, and blood components having adverse effects due to excessive or insufficient heat exchange. There is no way to receive it. Further, as described above, since the entire area inside the blood flow tank is effectively used for heat exchange, it is possible to achieve miniaturization of the heat exchanger. In addition, since the conventional baffle plate is not used to disperse and move the blood throughout the area where the tube group is installed, the blood does not collide with the baffle plate or the inner wall of the tank, and there is a risk of blood damage. Nor. That is, according to the present invention as set forth in claim 1,
The above objects can achieve the above-mentioned objects of the present invention. In addition, according to the present invention as described in claim 2, as will be described later, the above-mentioned object of the present invention can be better achieved while satisfying both the heat exchange performance and pressure loss of the heat exchanger. Embodiment FIG. 1 is a partially cutaway front view showing a blood heat exchanger according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the - line in FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view of the portion shown in FIG. 1. The blood heat exchanger 10 has a box 1 having a generally rectangular parallelepiped shape.
1, and the longitudinal direction of the box 11 is used as a horizontal state. A blood flow tank 12 having a blood storage chamber is formed at the center in the longitudinal direction inside the box 11, and the blood flow tank 12 has a wall 13 that partitions the inside of the box 11.
It is divided and formed by. That is, the blood flow tank 12 is formed with a pair of partition walls 13 disposed opposite to each other at a central position in the longitudinal direction inside the case 11, and each partition wall 13 is formed in a groove formed inside the case 11. 14 are fitted. Furthermore, a resin material 15 such as polyurethane is filled and solidified inside the blood flow tank 12 of each partition wall 13. Holes 16 are formed at the upper and lower positions of the opposing side walls of the blood flow tank 12 and at diagonal positions on a pair of sides of the box 11 shown in FIG. A blood inlet 17 is formed in the lower hole 16 of the hole 16, and a blood outlet 18 is formed in the upper hole 16, respectively. The blood inflow port 17 can be connected to a blood inflow pipe 20 that allows blood 19 taken out from the body to flow into the blood flow tank 12, and the blood outflow port 18
A blood outflow pipe 21 that can supply blood 19 from the blood flow tank 12 to the inside of the body can be connected to the blood flow tank 12 .
As a result, blood 1 flowing in from the blood inlet 17
9 passes through the blood flow tank 12 and flows out from the blood outlet 18. Inside the blood flow tank 12, a plurality of tube bodies 22 are disposed approximately in parallel in a vertically central portion between the blood inlet 17 and the blood outlet 18 to allow a heat exchange medium to pass therethrough. It is formed by a group of tubes that divide the inside of the tank into upper and lower sections. The tube bodies 22 are made of stainless steel, and are arranged in layers in parallel to each other. Both ends of the tube body 22 in the longitudinal direction (direction A) are supported by the partition wall 13 and the resin material 15, respectively. Inside the box 11, at both ends of the box 11 in the longitudinal direction relative to the blood flow tank 12, there are an inflow chamber 23 and an outflow chamber 24 that allow the heat exchange medium to flow into and out of the tube body 22.
are respectively formed, and the inflow chamber 23 is arranged at the left end side with respect to the blood flow tank 12 shown in FIG. 2, and the outflow chamber 24 is arranged at the right end side with respect to the blood flow tank 12. Further, each of the inflow chamber 23 and the outflow chamber 24 is isolated from the blood flow tank 12 by the partition wall 13 and the resin material 15. Furthermore, the inflow chamber 23
The inlet chamber 24 has a supply port 25 that allows the heat exchange medium to be supplied into the inflow chamber 23 , and the outflow chamber 24 has a supply port 25 that allows the heat exchange medium to be supplied into the inflow chamber 23 .
a discharge port 2 allowing the discharge of the heat exchange medium from 4;
6 are formed respectively. In the partition wall 13 that partitions the inflow chamber 23, a communication port 27 through which the heat exchange medium flows into the pipe body 22 is formed for each tube body, and in the partition wall 13 that partitions the outflow chamber 24, a pipe is formed. body 22
A communication port 28 is formed in each tube to allow the heat exchange medium therein to flow out into the outflow chamber 24. As a result, the heat exchange medium is transferred to the tube body 22 as shown in FIG.
From the inflow chamber 23 to the outflow chamber 2 while passing through the
4, and heat exchange of the blood 19 passing through the blood flow tank 12 becomes possible. Note that hot water, cold water, etc. can be used as the supplied heat exchange medium. A tube group 22A made up of tube bodies 22 disposed in the blood flow tank 12 has a constant length a in the longitudinal direction within the blood flow tank 12. Further, in the blood flow tank 12, the blood 19 flows from the bottom to the top in the illustrated example so as to be substantially orthogonal to the tube body, and the tube body group 22A is arranged in the flow path direction of the blood 19 [direction B]. ]
On the other hand, as shown in FIG. 3, the center portion of the box in the vertical direction has a constant length b and a constant width c. Thereby, the tube group 22A is connected to the blood flow tank 1.
2 has a substantially rectangular parallelepiped shape. In addition, the tube group 22A of the blood heat exchanger 10 according to this embodiment has a b/a ratio in the range of 0.7 to 1.5,
Further, the c/a ratio is in the range of 0.5 to 1.0. Furthermore, the tubes 22 constituting the tube group 22A are spaced apart from each other by a constant distance T, and are arranged in a manner that the tubes 22 form an equilateral triangle with each other, as shown in FIG. Ru. Blood flow adjustment chambers 29 and 30 are formed in the blood flow tank 12 at a lower position and an upper position, respectively, with respect to substantially the entire area where the tube group 22A is installed. The blood flow adjustment chambers 29 and 30 are connected to the hole 16
In addition to changing the flow direction so that the blood flowing in from or flowing out to the hole portion 16 does not go directly to the tube group, the flow rate of blood 19 passing through each tube body 22 arranged in a group is approximately equalized. The blood flow tank 12 can be adjusted so that an approximately equal amount of blood 19 flows from the bottom to the top in the direction of the arrow B in the length a direction of the tube body 22 and the width c direction of the tube body group 22A in the blood flow tank 12. That is, the blood flow adjustment chamber 29 located below the blood flow tank 12 is connected to the blood inlet 17 provided on the side thereof, and the blood 19 flowing into the blood flow tank 12 from the blood inlet 17 is connected to the blood flow adjustment chamber 29 .
By once filling the adjustment chamber, it is prevented from flowing directly into the tube group. As a result, the blood 19 filling the blood flow adjustment chamber 29 is
2 in the length a direction of the tube group 22A and in the width c direction of the tube group 22A, the flow rate of the blood 19 passing through each tube body 22 is made substantially equal. The blood 19 that passes through the blood flow tank 12 while threading between the tube bodies 22 is temporarily filled in the blood flow adjustment chamber 30 located above, and the blood 19 that is further filled in the blood flow adjustment chamber 30 is , the blood flows out from the blood outlet 18 connected to the blood flow adjustment chamber 30. This makes it possible for the blood 19 rising in the blood flow tank 12 to flow out sequentially while passing through the blood flow adjustment chamber 30, and in the length a direction of the tube body 22 and the width c direction of the tube group 22A. In,
Blood outflow port 18 from blood flow adjustment chamber 30 without affecting the flow of blood 19 that rises evenly.
The heat-exchanged blood 19 is allowed to sequentially flow out. Hereinafter, a case will be described in which the heat exchanger 10 according to the above embodiment is used in an extracorporeal circulation circuit of an oxygenator. FIG. 5 shows an extracorporeal circulation circuit of an artificial lung, in which blood 19 taken out from a vein in the body is being circulated to an artificial lung 32 by operation of a pump 31. artificial lung 3
The blood 19 that has been oxygenated in step 2 is sent to the blood heat exchanger 10 according to the above embodiment,
After the blood is heated back to normal blood temperature in the heat exchanger 10, it is again supplied to the arteries of the human body. That is, blood 19 passing through the artificial lung 32
This is because the temperature decreases due to the passage, and it is impossible to supply it to the human body in that state.
Note that the heat exchanger 10 uses hot water with a temperature of about 40°C. Thus, the heat exchanger 10 has the following effects. Blood inlet 1 opening into the blood flow tank 12
7 is located on the side surface of the space of the blood flow adjustment chamber 29 located below substantially the entire area of the installation area of the tube group 22A. Therefore, the blood that will flow in from the blood inflow port 17 first spreads to the entire space of the lower blood flow adjustment chamber 29, and then spreads over almost the entire area where the tube group 22A is installed. This results in the formation of an upward flow towards the area. In addition, a blood outflow port 18 inside the blood flow tank 12
A space for a blood flow adjustment chamber 30 located above substantially the entire area of the installation area of the tube group 22A is formed in the opening portion. Therefore, the blood rising in substantially the entire area of the installation area of the tube group 22A as described above is in a state where large back pressure resistance is not formed in substantially the entire area on the side of the upper blood flow adjustment chamber 30. The blood flows into the entire space of the blood flow adjustment chamber 30, and then flows into the entire space of the blood flow adjustment chamber 3.
The blood flows out from the blood outlet 18 opened on the side of the blood. Therefore, according to the above, blood flow tank 1
2, the blood passes through the blood inlet 1 as in the conventional case.
7 to the blood outflow port 18 without moving in a short-circuit manner, the tube group 22A moves in a uniformly distributed manner over the entire installation area. As a result, the flow rate of blood passing through the tube body group 22A is not excessive or insufficient locally in both areas where the tube body group 22A is installed, and all the blood can be equally heat exchanged, and the blood components are not affected by excessive or insufficient heat exchange. There will be no adverse effects. Further, as described above, since the entire area inside the blood flow tank 12 is effectively used for heat exchange, the size of the heat exchanger 10 can be reduced. Furthermore, since the conventional baffle plate is not used to disperse and move the blood throughout the installation area of the tube group 22A, the blood does not collide with the baffle plate or the inner wall of the tank, thereby preventing blood damage. I won't wake you up. That is, according to the above-mentioned embodiment, all the blood passing through the blood flow tank 12 can be equally heat-exchanged using the heat exchanger 10 which is small and causes little blood damage. Next, we will discuss a blood heat exchanger as an example of the present invention having the configuration of the above embodiment, and a blood inflow port of a blood flow tank so that blood flows directly into a tube group without going through a blood flow adjustment chamber or the like. Blood was passed through each blood heat exchanger as a comparative example provided on the bottom to conduct an experiment on heat exchange efficiency. In addition, each of the heat exchangers used in the experiment has a blood flow tank of the same shape and capacity, and the tube group is composed of 500 stainless steel pipes.
The length a in the longitudinal direction of the tube in the blood flow tank is
The length b of the tube group in the flow path direction was 74 mm, and the width C of the tube group in the flow path direction was 56 mm. As a result, the b/a ratio was 1.06 and the c/a ratio was 0.80. The stainless steel pipe used had a wire gauge of 16 (inner diameter 1.45 mm, wall thickness 0.1 mm). Further, hot water was used as a heat exchange medium, the flow rate of the hot water was 10/min, and the temperature at the supply port was 40°C. In the experiment, the blood temperatures at the blood inlet and blood outlet were measured, and the heat exchange efficiency of each blood heat exchanger was measured. The experiment was conducted once for each blood flow rate of 3.0/min and 5.0/min, using bovine blood adjusted to a hematocrit value of 35%. Table 1 shows the experimental results, and as shown by the results, the blood heat exchanger according to the present invention, which has an inlet on the side of the blood flow adjustment chamber, can obtain sufficient heat exchange performance. I found out. In addition, we assumed that the blood flow could be visually stimulated in the experiment, and as a result of observing the flow, the heat exchanger was installed in the blood flow adjustment chamber to prevent the inflowing blood from directly flowing into the tube group. By providing an inlet on the side of the tube, it is visually observed that the blood is raised evenly in the length a direction of the tube body and the width c direction of the tube group, and all the tube bodies contribute sufficiently to heat exchange. It was confirmed that On the other hand, in the exchanger of
It was confirmed that the blood that flowed in from the inlet at the bottom of the blood flow tank directly flowed into the tube group, and that the flow rate of blood passing through each tube was different at each position. From this, it can be seen that heat exchange of blood is performed more evenly in the heat exchanger. Next, in the blood heat exchanger 10 according to the above embodiment, the length b and width c of the tube group 22A with respect to the blood flow path direction [B direction] are changed, respectively.

[Table] The heat exchange capacity and pressure drop were measured in the following cases. Each heat exchanger used in the experiment is a tube group 22.
A was made up of 500 16-gauge stainless steel pipes, and the length a of the tube body 22 in the blood flow tank 12 in the longitudinal direction was 70 mm. Furthermore, hot water is used as a heat exchange medium, and the hot water has a flow rate of 10/
min, and the temperature at the supply port 25 was 40°C. The experiment was carried out using No. 1 to No. 3 with different values of b and c.
The experiment was carried out using two blood heat exchangers, and the temperature of the blood 19 at the blood outlet 18 was measured relative to the temperature of the blood 19 at the blood inlet 17 of 30°C. At the same time, pressure loss was also measured. In addition, the experiment was conducted at a blood flow rate of 5.0/min, and the blood had a hematocrit value of 35%.
Bovine blood adjusted to Table 2 shows the experimental results, and as shown in the results, in order to obtain a high heat exchange capacity, the length b of the tube group 22A with respect to the blood flow path direction [B direction] is increased, and the tube body It is preferable to reduce the width c of the group 22A, and in order to keep the pressure loss small, the tube group 22 in the blood flow path direction [direction B]
It can be seen that it is preferable to decrease the length b of A and increase the width c of the tube group 22A. Therefore,
In order to satisfy both heat exchange capacity and pressure loss, it is most preferable to balance each value of b and c. Therefore, the ratio of b/a is 0.7 to 1.5, and the ratio of c/a is A range of 0.5 to 1.0 is considered appropriate.

[Table] Effects of the invention As described above, according to the invention, all the blood passing through the blood flow tank can be evenly heat-exchanged using a small-sized heat exchanger that causes little blood damage.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a blood heat exchanger according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a - in FIG. 1. 4 is an enlarged sectional view of the part shown in FIG. 1, and FIG. 5 is an oxygenator constructed using a blood heat exchanger according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an extracorporeal circulation circuit. 10...Blood heat exchanger, 12...Blood flow tank,
17...Blood inlet, 18...Blood outlet, 19
...Blood, 22...Tube body, 29,30...Blood flow adjustment chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A blood flow tank having a blood inlet at the bottom and a blood outlet at the top, and blood flowing from the blood inlet to the blood outlet within the blood flow tank. A tube group consisting of a plurality of tubes that cross the blood flow, are arranged in parallel with each other and extend outside the blood flow tank, and allow a heat exchange medium to pass therethrough, and a heat exchanger that communicates with both ends of each tube. In a blood heat exchanger having an inlet and an outlet for an exchange medium, spaces forming blood flow adjustment chambers are provided below and above, respectively, substantially the entire area of the tube group installation area in the blood flow tank. . A heat exchanger for blood, characterized in that each of the blood inflow port and the blood outflow port is opened on a side surface of each of the corresponding blood flow adjustment chambers. (2) Let the length of each tube in the blood flow tank be a,
Let b be the length of the tube group along the blood passage direction in a cross section perpendicular to the longitudinal direction of the tube group, and c be the width of the tube group in the direction perpendicular to the blood passage direction in the cross section. when doing,
The ratio of b/a is in the range of 0.7 to 1.5, and c/a
1. The blood heat exchanger according to claim 1, wherein the ratio of 0.5 to 1.0.