The present invention relates to a preparation apparatus and a preparation method for preparing a concentrated solution for dialysis solution by dissolving a solid formulation for dialysis solution in a predetermined amount of water.
BACKGROUND ART [0002]
There are cases where as the solid formulation for dialysis solution, an A agent containing an electrolyte component or the like and a B agent containing sodium bicarbonate as a principal component are used. To prepare the dialysis solution, an A concentrated solution prepared by dissolving an A agent in water and a B concentrated solution prepared by dissolving a B agent in water are diluted at a predetermined ratio and with a predetermined amount of water. Preparation of these is performed when the dialysis solution is used. Conventionally, preparation of these has been performed by using a winged agitator. That is, as shown in FIG. 15, water and a solid formulation for dialysis solution

are thrown in a tank 1 and these are agitated by a winged agitator 9, whereby the solid formulation for dialysis solution is dissolved in water.
PRIOR ART DOCUMENTS
[Patent Documents]
[0003]
[Patent Document 1] Japanese Patent No. 4418019 [Patent Document 2] Japanese Patent No. 5690438
SUMMARY OF THE INVENTION
[Problem to be Solved by the Invention]
[0004]
However, when preparation is performed by using the winged agitator 9, in particular, in the preparation of the B concentrated solution, the following problems arise:
(a) A comparatively long dissolution time is required;
therefore, workability is poor.
(b) There are cases where dissolution is impossible depending on the amount of water.
(c) There are cases where pH largely fluctuates by the agitation causing the water surface to bubble to generate carbon dioxide.
[0005]
Although a centrifugal agitator different from the

winged agitator 9 is shown in Patent Document 1, the use of the centrifugal agitator for the preparation of the concentrated solution for dialysis solution is not shown at all. [0006]
An object of the present invention is to provide a preparation apparatus and a preparation method capable of solving problems as mentioned above.
[Means for Solving the Problem]
[0007]
A first aspect of the present invention is a preparation apparatus that prepares a concentrated solution for dialysis solution by dissolving a solid formulation for dialysis solution in a predetermined amount of water. The preparation apparatus is provided with: a tank for storing the predetermined amount of water; a centrifugal agitator placed in the tank so that the water stored in the tank can be agitated; and a driving portion that rotates the agitator. The centrifugal agitator is provided so as to rotate by a vertical rotation shaft, has on its surface an inlet and an outlet communicating with the inlet through an internal flow passage, and sucks the water from the inlet and discharges the water from the outlet by way of the internal flow passage by centrifugal force.

[0008]
A second aspect of the present invention is a preparation method for preparing a concentrated solution for dialysis solution by dissolving a solid formulation for dialysis solution in a predetermined amount of water. The preparation method is provided with an agitating step of agitating, by a centrifugal agitator, the water in the tank in which the solid formulation for dialysis solution is thrown. The centrifugal agitator is provided so as to rotate by a vertical rotation shaft, has on its surface an inlet and an outlet communicating with the inlet through an internal flow passage, and sucks the water from the inlet and discharges the water from the outlet by way of the internal flow passage by centrifugal force. In the agitating step, when a vertical distance between the water surface of the water stored in the tank and the center of the outlet of the agitator is a first distance, the agitator is rotated at a first rotation speed and when the vertical distance is a second distance, the agitator is rotated at a second rotation speed. The second distance is set so as to be shorter than the first distance, and the second rotation speed is set to a speed lower than the first rotation speed.
[Effects of the Invention] [0009]
According to the present invention, since agitation is

performed by the centrifugal agitator, the water in the tank can be evenly agitated in an effective manner. Consequently, the dissolution time can be reduced, so that workability can be improved. In particular, in the case of a B concentrated solution prepared by dissolving a B agent containing sodium bicarbonate as a principal component in water, the fluctuation of the pH value can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS [0010]
FIG. 1 is an overall perspective view showing a preparation apparatus of an embodiment of the present invention,-
FIG. 2 is a partial cross-sectional front segmentary view of a tank;
FIG. 3 is a lower perspective view of a centrifugal agitator;
FIG. 4 is a view on arrow IV of FIG. 3;
FIG. 5 is a front cross-sectional view showing water flows caused by the centrifugal agitator,-
FIG. 6 is a perspective view showing a spacer member,-
FIG. 7 is a front view showing a condition where the tank is inclined by the spacer member;
FIG. 8 is a view showing the preparation results when a height position H is changed;

FIG. 9 is a view showing the preparation results when the rotation speed of the centrifugal agitator is changed;
FIG. 10 is a view showing the preparation results for each water amount in the case of a first rotation speed;
FIG. 11 is a view showing the preparation results for each water amount in the case of a second rotation speed;
FIG. 12 is a view showing the relation between the tank inclination angle and the residual solution amount in the tank;
FIG. 13 is a view showing the results of preparation by the preparation apparatus of the present embodiment;
FIG. 14 is a view showing the results of comparison with a case where a winged agitator is used; and
FIG. 15 is a partial cross-sectional front segmentary view of the conventional apparatus using the winged agitator.
MODE FOR CARRYING OUT THE INVENTION
[0011]
FIG. 1 is an overall perspective view showing a preparation apparatus of an embodiment of the present invention. This preparation apparatus 10 is provided with a tank 1 for storing a predetermined amount of water, a centrifugal agitator 2 placed in the tank 1 so that the water stored in the tank 1 can be agitated, and a driving portion 3 that rotates the agitator 2.
[0012]

The tank 1 is placed on a table 4 . To the driving portion 3, a driving control portion 5 is connected. To a discharging port 11 of the tank 1, an external outflow pipe 12 is coupled. An end of the external outflow pipe 12 is coupled to a storage reservoir 6 situated below the table 4 through a filter member for preventing an undissolved solid formulation for dialysis solution, foreign substances and the like from flowing out from the tank 1. [0013]
FIG. 2 is a partial cross-sectional front segmentary view of the tank 1. FIG. 3 is a lower perspective view of the centrifugal agitator 2. FIG. 4 is a view on arrow IV of FIG. 3. The tank 1 is an upward opening cylindrical body. A side surface 101 of the tank 1 is marked with a scale indicative of the amount of water. The centrifugal agitator 2 is provided so as to rotate by a vertical rotation shaft 20, and has, on its surface, inlets 21 and outlets 23 communicating with the inlets 21 through internal flow passages 22 . Here, five inlets 21 having the same size are formed at regular intervals in the circumferential direction on a lower surface 28 of the agitator 2 . The internal flow passages 22 extend upward vertically from the inlets 21 and further extend laterally to communicate with the outlets 23. On a peripheral surface 29 of the agitator 2, five outlets 23 having the same size are formed at regular intervals. The centrifugal agitator 2 is disposed in the

center of the tank 1 and in a predetermined height position H (FIG. 5) . The height position H is a distance from a bottom surface 102 of the tank 1 to the center of the outlets 23.
[0014]
The centrifugal agitator 2 having the above-described structure causes water flows as shown in FIG. 5 when the water in the tank 1 is agitated. That is, when the agitator 2 rotates, water flows A are caused where water is sucked in from the inlets 21, passes through the internal flow passages 22 and is discharged from the outlets 23. Along with the water flows A, the following water flows are caused: water flows B where water in an upper part of the agitator 2 is agitated; water flows C heading downward from the agitator 2; and water flows D where water is agitated upward from the center of the bottom surface 102 of the tank 1. As described above, according to the agitator 2, the water in the tank 1 can be evenly agitated in an effective manner with the water surface Z being hardly-ruffled. The centrifugal agitator 2 of FIG. 5 corresponds to the V-V cross-sectional view of FIG. 4.
[0015]
The discharging port 11 is provided in the neighborhood of the bottom of the side surface 101 of the tank 1. To the discharging port 11, an internal inflow passage 13 is coupled. The inflow opening 131 at an end of the internal inflow passage 13 is situated at a slight gap W with respect to the bottom

surface 102 of the tank 1. Therefore, at the discharging port 11, the siphon principle acts since the internal inflow passage 13 and the external outflow pipe 12 are provided. The center of the discharging port 11 is situated at a vertical distance Tl from the bottom surface 102, and the center of an inflow opening 131 is situated at a horizontal distance T2 from the side surface 101. [0016]
The preparation apparatus 10 further has an inclining mechanism for inclining the tank 1 toward the discharging port 11. Specifically, as shown in FIG. 6, a spacer member 41 to be inserted below the bottom surface 102 of the tank 1 is provided on the side, of the tank 1, opposite to the discharging port 11. The spacer member 41 consists of a spacer main body 411 and a handle 412, and the spacer main body 411 is inserted and taken out below the bottom surface 102 of the tank 1 by rotating the handle 412 around a shaft 413 in the direction of the arrow R. The spacer member 41 inclines the tank 1 an
angle a (FIG. 7) with respect to the horizon by inserting the
spacer main body 411 below the bottom surface 102.
[0017]
The driving control portion 5 controls the driving portion 3 so as to switch the rotation speed S of the agitator 2 between a first rotation speed SI and a second rotation speed S2 . That is, as shown in FIG. 5, the driving control portion

5 can adopt the first rotation speed SI when the vertical distance L between the water surface Z of the water stored in the tank 1 and the center of the outlets 23 of the agitator 2 is a first distance LI, and can adopt the second rotation speed S2 when the vertical distance Lisa second distance L2 . Here, L1>L2, and S1>S2. [0018]
When the solid formulation for dialysis solution contains sodium bicarbonate as a principal component, that is, when the B concentrated solution is prepared by dissolving the B agent in water, the first rotation speed SI adopted when the vertical distance L is the first distance LI is set to a value where no bubbling due to agitation occurs on the water surface Z, and the second rotation speed S2 adopted when the vertical distance L is the second distance L2 is set to a value where no bubbling due to agitation occurs on the water surface Z. In the present specification, the "B agent containing sodium bicarbonate as a principal component" indicates a B agent containing only sodium bicarbonate and a B agent containing, for example, a small amount of additive such as sodium chloride in addition to sodium bicarbonate. [0019]
Next, a case will be described in which by using the preparation apparatus 10 having the above-described structure, the B concentrated solution is prepared by dissolving, for

example, the B agent containing sodium bicarbonate as a principal component in water.
(1) First, the B agent as the solid formulation for
dialysis solution and a predetermined amount V of water are
thrown in the tank 1.
[0020]
(2) Then, the rotation speed S of the agitator 2 is set
to the first rotation speed SI or the second rotation speed
S2 by the driving control portion 5, and the agitator 2 is
actuated to agitate the B agent and the water in the tank 1
(agitating step). In doing this, the vertical distance L
between the water surface Z of the water stored in the tank 1 and the center of the outlets 23 of the agitator 2 is measured
(or read from the scale on the tank 1), when it is the first distance LI, the first rotation speed SI is adopted, and when it is the second distance L2, the second rotation speed S2 is adopted. That is, agitation by the agitator 2 is performed so that no bubbling occurs on the water surface Z. Agitation is performed until all the B agent being thrown is dissolved in the water. Thereby, the B concentrated solution is prepared.
[0021]
(3) Then, after agitation is finished, the closed
discharging port 11 is opened, and the B concentrated solution
is discharged from the discharging port 11 into the storage

reservoir 6 through the external outflow pipe 12 and the filter member provided at the end thereof (discharging step). In doing this, the B concentrated solution is discharged from the discharging port 11 due to its own weight only by opening the discharging port 11, and since the siphon principle acts at the discharging port 11, the solution is discharged to a degree that a small amount VI is left at the bottom in the tank 1 at the end stage of the discharging. At the end stage of the discharging, as shown in FIG. 7, the tank 1 is lifted up, the spacer member 41 is operated to insert the spacer main body 411 below the bottom surface 102 of the tank 1 so that the tank 1 is inclined at an angle a toward the discharging port 11, and discharging is performed under this inclined condition. Thereby, almost all amount of the B concentrated solution is discharged, and only an extremely small amount V2 is left at the bottom in the tank 1. Moreover, since the filter member is provided at the end of the external outflow pipe 12, the undissolved B agent in the tank 1 can be prevented from flowing out of the tank 1. [0022]
According to the preparation apparatus 10 having the above-described structure, the following effects are produced:
(a) Since agitation is performed by the centrifugal agitator 2, the water in the tank 1 can be evenly agitated in

an effective manner. Consequently, all the B agent being thrown can be dissolved in water in a short time, that is, the dissolution time can be reduced, so that workability can be improved. [0023]
(b) Since agitation is performed with the rotation speed
S of the agitator 2 being set to the first rotation speed SI
or the second rotation speed S2, that is, so that no bubbling
occurs on the water surface Z, the generation of carbon dioxide
when the sodium bicarbonate as a principal component of the
B agent is dissolved can be suppressed. Consequently, a B
concentrated solution with a desired pH value can be prepared
while the fluctuation in pH is suppressed.
[0024]
(c) Since the siphon principle is used in the discharging
of the B concentrated solution from the discharging port 11,
the B concentrated solution can be surely discharged to a degree
that a comparatively small amount VI is left in the tank 1.
[0025]
(d) Further, since the B concentrated solution is
discharged with the tank 1 being inclined toward the
discharging port 11, only an extremely small amount V2 is left
in the tank 1, and substantially all amount of B concentrated
solution can be discharged.

EXAMPLE
[0026]
[Actual machine]
Using the preparation apparatus 10 defined by the following numerical values, the B concentrated solution was prepared, and further, discharged:
• Tank 1
• Bottom area: 14 80 cm2
• Internal capacity: 100 liters
• Discharging port 11

• Vertical distance Tl: 60 mm
• Horizontal distance T2: 28.5 mm
• Gap W: 0.5 mm
• Centrifugal agitator 2
• Height position H (FIG. 5): 150 mm
• Disposed in the center of the tank 1

• First distance LI: not less than 200 mm (not less than 50 liters)
• Second distance L2: not more than 200 mm (not more than 50 liters)
• First rotation speed SI: 1145 rpm
• Second rotation speed S2: 750 rpm
• Inclination angle a (FIG. 7): 12.5 degrees [0027]
Grounds for the adoption of the above numerical values

are as follows: (Height position H)
Sixty liters of water with a temperature of 18 degrees C and 4.8 kg of sodium bicarbonate were thrown in the tank 1, and the centrifugal agitator 2 was rotated at a rotation speed of 90 0 rpm to perform agitation. As the height position H of the centrifugal agitator 2, the following three cases were adopted: a case of 100 mm; a case of 150 mm; and a case of 200 mm. The results are shown in FIG. 8. [0028]
As is apparent from FIG. 8, in the case of 150 mm, the dissolution time was shortest and the pH value was lowest. Therefore, 150 mm is adopted as the height position H. [0029] (First rotation speed SI and second rotation speed S2)
The height position H of the centrifugal agitator 2 was set to 150 mm, 60 liters of water with a temperature of 18 degrees C and 4.8 kg of sodium bicarbonate were thrown in the tank 1, and the centrifugal agitator 2 was rotated to perform agitation. Here, as the rotation speed of the centrifugal agitator 2, five rotation speeds in a range of 400 to 1200 rpm were adopted. The results are shown in FIG. 9. [0030]
As is apparent from FIG. 9, as a rotation speed satisfying the condition that the dissolution time is short and the pH

value is low, 750 rpm can be adopted as a low speed, and 1145 rpm can be adopted as a high speed. Therefore, 1145 rpm was adopted as the first rotation speed SI, and 750 rpm was adopted as the second rotation speed S2. [0031] (First distance LI)
The height position H of the centrifugal agitator 2 was set to 150 mm, water with a temperature of 20 degrees C and sodium bicarbonate were thrown in the tank 1, and the centrifugal agitator 2 was rotated at 1145 rpm to perform agitation. Here, as the amounts of water and sodium bicarbonate to be thrown in, five cases were adopted. That is, cases of "40 liters, 3 .2 kg" , "50 liters, 4 .0 kg", "60 liters, 4.8 kg", "80 liters, 6.4 kg" and "100 liters, 8.0 kg" were adopted. [0032]
As is apparent from FIG. 10, it was a case of not less than 50 liters that satisfied the condition that the dissolution time is short and the pH value is low. In the case where the water was 50 liters, the vertical distance L between the water surface Z of the water in the tank 1 and the center of the outlets 23 of the centrifugal agitator 2 is 200 mm. Therefore, not less than 200 mm was adopted as the first distance LI. [0033]

(Second distance L2)
The height position H of the centrifugal agitator 2 was set to 150 mm, water with a temperature of 18 degrees C and sodium bicarbonate were thrown in the tank 1, and the centrifugal agitator 2 was rotated at 750 rpm to perform agitation. Here, as the amounts of water and sodium bicarbonate to be thrown in, six cases were adopted. That is, cases of "30 liters, 2.4 kg", "40 liters, 3.2 kg", "50 liters, 4.0 kg", "60 liters, 4 .8 kg", "80 liters, 6.4 kg" and "100 liters, 8.0 kg" were adopted. [0034]
As is apparent from FIG. 11, it was a case of not more than 50 liters that satisfied the condition that the dissolution time is short and the pH value is low. The vertical distance L when water is 50 liters is 200 mm. Therefore, not more than 200 mm was adopted as the second distance L2. [0035] (Inclination angle a)
The B concentrated solution having been prepared was discharged from the discharging port 11. In doing this, at the end stage of the discharging, as the inclination angle of the tank 1, the following four cases were adopted: 2 degrees; 3 degrees; 6.5 degrees; and 12.5 degrees. [0036]
As shown in Table 1 and FIG. 12, when the tank 1 was not

inclined, the amount of B concentrated solution left in the tank 1, that is, the residual solution amount VI was 370 mL. On the other hand, it was 580 mL when the siphon principle was not adopted for the discharging port 11. Thereby, according to the above-described actual machine of the preparation apparatus 10, even when the tank 1 is not inclined, the residual solution amount can be reduced more than before. [0037]
When the tank 1 is inclined, the residual solution amount can be reduced more . In particular, when the inclination angle is 12.5 degrees, since the residual solution amount V2 is 8 mL, almost all amount of B concentrated solution can be discharged. Therefore, 12. 5 degrees was adopted as the inclination angle a. [0038]

(Results)
The results of the preparation of the B concentrated

solution by using the above-described actual machine of the preparation apparatus 10 are as shown in FIG. 13. Regarding the case of 50 liters, either of the first rotation speed SI and the second rotation speed S2 may be adopted. [0040] (Comparison with winged agitator)
Using the winged agitator 9, the dissolution time and the pH value were measured while the height position H was set to 14 0 mm, the rotation speed was set to 6 0 rpm and the others were similar to those in the case of the above-described actual machine of the preparation apparatus 10 . The results are shown in FIG. 14. [0041]
As is apparent from FIG. 14, when the winged agitator 9 was used, the dissolution time was long and the pH value was comparatively high compared with when the centrifugal agitator 2 was used. [0042]
Further, when the winged agitator 9 was used, there are cases where dissolution was impossible depending on the amount of water. For example, in the case of 60 liters, dissolution was impossible. The reason is inferred as follows: In the case of the winged agitator 9, the ascending water flows caused by the wing and the descending water flows due to the own weight of the water countervail against each other at the water level

in the neighborhood of 60 liters, and as a result, the agitating force is weakened. On the contrary, when the centrifugal agitator 2 is used, such a disadvantage is not produced. [0043] [Modifications]
(1) It is preferable to switch the rotation speed S of
the centrifugal agitator 2 between the first rotation speed
SI and the second rotation speed S2 like the preparation
apparatus 10 having the above-described structure. However,
the rotation speed may be set to a constant speed that is between
750 and 1145 rpm without being switched. Even in that case,
as shown in FIGS. 9 and 14, the condition that the dissolution
time is short and the pH value is low is satisfied. In FIG.
14, the rotation speed of the centrifugal agitator 2 is set
to 750 rpm.
[0044]
(2) The preparation apparatus 10 having the
above-described structure may be used for the preparation of
the A concentrated solution.
INDUSTRIAL APPLICABILITY [0045]
The preparation apparatus and the preparation method of the present invention are high in industrial utility value since they are capable of improving workability by reducing

the dissolution time and, in particular, capable of preparing a B concentration solution with a desired pH value.
EXPLANATION OF REFERENCE NUMERALS [0046]
1: Tank
11: discharging port
12: external outflow pipe
13: internal inflow passage
131: inflow opening
101: side surface
102: bottom surface
2: centrifugal agitator
20: vertical rotation shaft
21: inlet
22: internal flow passage
23: outlet
3: driving portion
5: driving control portion.

CLAIMS
1. A preparation apparatus that prepares a concentrated
solution for dialysis solution by dissolving a solid
formulation for dialysis solution in a predetermined amount
of water, the preparation apparatus comprising:
a tank for storing the predetermined amount of water;
a centrifugal agitator placed in the tank so that the water stored in the tank can be agitated; and
a driving portion that rotates the agitator,
wherein the centrifugal agitator is provided so as to rotate by a vertical rotation shaft, has on its surface an inlet and an outlet communicating with the inlet through an internal flow passage, and sucks the water from the inlet and discharges the water from the outlet by way of the internal flow passage by centrifugal force.
2. The preparation apparatus according to claim 1,
further comprising a driving control portion that controls the
driving portion so as to switch a rotation speed of the agitator
between a first rotation speed and a second rotation speed,
wherein the driving control portion can adopt the first rotation speed when a vertical distance between a water surface of the water stored in the tank and a center of the outlet of the agitator is a first distance, and can adopt the second

rotation speed when the vertical distance is a second distance, the second distance is set so as to be shorter than the
first distance, and
the second rotation speed is set to a speed lower than
the first rotation speed.
3. The preparation apparatus according to claim 2,
wherein the solid formulation for dialysis solution
contains sodium bicarbonate as a principal component,
the first rotation speed is set to a value where no
bubbling due to agitation occurs on the water surface when the
vertical distance is the first distance, and
the second rotation speed is set to a value where no
bubbling due to agitation occurs on the water surface when the
vertical distance is the second distance.
4. The preparation apparatus according to claim 2 or
3,
wherein the tank has a bottom area of 14 80 cm2 and an internal capacity of 100 liters,
the agitator is disposed in a position where the vertical distance between a bottom surface of the tank and the center of the outlet is 150 mm and in a center of the tank,
the first distance is not less than 200 mm,
the second distance is not more than 200 mm,

the first rotation speed is 1145 rpm, and the second rotation speed is 750 rpm.
5. The preparation apparatus according to any one of
claims 1 to 4,
wherein the tank has a discharging port in a neighborhood of a bottom of a side surface,
the discharging port has an internal inflow passage and an inflow opening at an end of the internal inflow passage is situated at a slight gap with respect to the bottom surface of the tank, and
to the discharging port, an external outflow pipe extending to a position lower than the bottom surface of the tank is coupled.
6. The preparation apparatus according to claim 5,
further comprising an inclining mechanism for inclining the
tank toward the discharging port.
7. The preparation apparatus according to claim 6,
wherein the inclining mechanism has a spacer member
inserted below the tank and inclining the tank so as to be lifted up.
8. The preparation apparatus according to claim 6 or

7,
wherein the inclining mechanism inclines the tank 2 to 12.5 degrees with respect to the horizon.
9. A preparation method for preparing a concentrated solution for dialysis solution by dissolving a solid formulation for dialysis solution in a predetermined amount of water, the preparation method comprising:
an agitating step of agitating, by a centrifugal agitator, the water in the tank in which the solid formulation for dialysis solution is thrown,
wherein the centrifugal agitator is provided so as to rotate by a vertical rotation shaft, has on its surface an inlet and an outlet communicating with the inlet through an internal flow passage, and sucks the water from the inlet and discharges the water from the outlet by way of the internal flow passage by centrifugal force,
in the agitating step, when a vertical distance between a water surface of the water stored in the tank and a center of the outlet of the agitator is a first distance, the agitator is rotated at a first rotation speed and when the vertical distance is a second distance, the agitator is rotated at a second rotation speed,
the second distance is set so as to be shorter than the first distance, and

the second rotation speed is set to a speed lower than the first rotation speed.
10. The preparation method according to claim 9,
wherein the solid formulation for dialysis solution is
sodium bicarbonate, and
in the agitating step, the agitator is rotated so that no bubbling due to agitation occurs on the water surface.
11. The preparation method according to claim 9 or 10,
wherein the tank has a discharging port in a neighborhood
of a bottom of a side surface,
the discharging port has an internal inflow passage and an inflow opening at an end of the internal inflow passage is situated at a slight gap with respect to a bottom surface of the tank, and
to the discharging port, an external outflow pipe extending to a position lower than the bottom surface of the tank is coupled,
a discharging step of discharging the concentrated solution for dialysis solution prepared by the agitation from the discharging port is further provided, and
in the discharging step, discharging is performed with the tank being inclined toward the discharging port at least at an end stage of the discharging.

12. The preparation method according to claim 11, wherein in the discharging step, the tank is inclined 2 to 12.5 degrees with respect to the horizon.