JPH0549869A - Concentration adjusting device of dialyzable liquid - Google Patents

Abstract

PURPOSE:To rapidly adjust the concentration of a dialyzable liquid to a target value and to stably supply the liquid at this concentration. CONSTITUTION:A liquid supplying pump 10 is drived at a specified flow rate, an original liquid of a dialyzable liquid supplied from dialyzable original-liquid supplying lines 2 and 3 is flown to mixing tanks 6 and 7 at a specified flow rate by dialyzable original liquid pouring pumps 4 and 5 and is diluted by a water supplied from a line 1 and mixed. The concentrations of chemicals in the mixed liquid is determined by concentration sensors 8 and 9 and the flow rate of the dialyzable original liquid pouring pumps is controlled. When adjustment of concentration is begun, the dialyzable original liquid pouring pumps are begun to drive at the specified flow rate and after rapidly getting near to the target value of concentration, the liquid flow rate by the dialyzable original liquid pouring pumps is varied corresponding to the concentration determined by the concentration sensors to adjust concentration so as to stably keep the concentration at a target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dialysate concentration adjusting device for a personal dialysis device or a dialysate supply device for a large number of people.

[0002]

2. Description of the Related Art In performing artificial dialysis, it is necessary to stably adjust the concentration of a dialysate in a hemodialysis machine to a target concentration.
From a therapeutic point of view, it is effective and important in terms of prescription, and reaching the target concentration quickly is suitable for performing dialysis economically and efficiently. Recently, a concentrated aqueous solution containing sodium chloride, potassium chloride, sodium acetate, etc., which are the main components of the dialysate (hereinafter referred to as "A stock solution"), and a concentrated aqueous solution of sodium hydrogencarbonate as one component of the dialysate ( Hereinafter, dialysis using a bicarbonate dialysate prepared by diluting and mixing the above two solutions with water has been generally performed by preparing two solutions (hereinafter, referred to as B stock solution).

[0003]

When the dialysate stock solution and the concentrated stock solution of sodium hydrogencarbonate are always supplied with a guaranteed constant concentration, these two stock solutions and water are used to obtain the dialysate. It may be mixed and diluted in a predetermined volume ratio according to the prescription. However, sodium hydrogen carbonate is often supplied in the form of powder, and must be dissolved in water to form an aqueous solution and a concentrated stock solution before use. Thus, when sodium hydrogen carbonate is supplied in the form of powder, it is difficult to always prepare a concentrated stock solution of sodium hydrogen carbonate as an aqueous solution having an accurate concentration. Therefore, when the dialysate is adjusted so that the volume ratio becomes constant by interlocking the feed flow rates of the dialysate pump and the dialysate stock injection pump with the metering pumps, the mixing rate of the dialysate stock solution is adjusted. If the concentration is not exactly diluted to the specified concentration, the target concentration will not be reached as shown in FIG. 4, and the concentration will remain constant with an error (FIG. 4 shows dialysis from the start of concentration adjustment). It is a figure which shows the density | concentration of a liquid, a horizontal axis shows time in the figure, and the vertical axis | shaft has shown the density | concentration of a dialysate.).

A concentration sensor is used to perform proportional control, derivative control, integral control, or a composite type control thereof so that a required concentration is achieved, and the dialysate is supplied by changing the flow rate of the dialysate concentrate injection pump. In the adjustment method, it takes a considerable amount of time for the diluted solution to become uniform in the mixing tank.Therefore, the flow rate of the dialysate stock solution injection pump at the time of dilution and the time until the concentration sensor detects the concentration Time difference occurs. Therefore, it is difficult to determine the control constant, and it is difficult to perform optimum control, and it takes a considerable time to stabilize the target concentration as shown in FIG. Defects such as were remarkable.

Therefore, in the conventional apparatus, the concentration cannot be adjusted accurately, or even if the concentration can be adjusted accurately, it takes time, and a large amount of dialysate is wasted during that time. An object of the present invention is to solve the above-mentioned problems and to provide a dialysate concentration adjusting device that allows a dialysate concentration to reach a target concentration quickly and maintains the concentration stably.

[0006]

The present invention is directed to a water supply line, a dialysate stock solution supply line, and a dialysate stock solution injection pump for delivering the dialysate stock solution supplied from the dialysate stock solution supply line at a predetermined flow rate. A mixing tank for diluting and mixing the dialysate stock solution supplied from the dialysate stock solution injection pump with water supplied from the water supply line; a concentration sensor for measuring the concentration of the mixed chemical solution; From a liquid supply pump that supplies a dialysate prepared by a liquid concentrate and water to a dialyzer, and a control unit that receives a signal from the concentration sensor and controls the flow rate of the dialysate concentrate injection pump. When the concentration is outside the predetermined concentration range determined in advance, the concentration measured by the concentration sensor reaches the predetermined concentration range determined in advance or Then, for a predetermined period of time, the concentration of the dialysate stock solution injection pump was adjusted at a predetermined flow rate, and when the concentration was within the predetermined range, it was measured by the concentration sensor. It is characterized in that the flow rate of the dialysate stock solution injection pump is changed according to the concentration to adjust the concentration.

Further, in the present invention, when the concentration is within the above-mentioned predetermined range, the flow rate of the dialysate stock solution injection pump is adjusted by changing it. The liquid flow rate is maintained or the concentration is adjusted until it is within an allowable error with a predetermined target concentration.
Then, the concentration measurement by the chemical concentration sensor is repeated so that the concentration of the dialysate falls within an allowable error with respect to the predetermined target concentration.

In the calculation of the change in the delivery flow rate of the dialysate stock solution injecting pump, various controls by proportional control, derivative control, integral control or a combination of these, and other microcomputers can be used. When the difference from the target density is large, it is possible to perform arithmetic processing such as restricting the maximum value of the change width so as to gradually approach the target density. Further, as the value of the initial flow rate of the dialysate undiluted solution injection pump, it is preferable to use the solution delivery flow rate when the concentration is stably adjusted to the target value.

[0009]

[Function] The concentration of the dialysate is adjusted in the following order. That is, Step 1: When the concentration adjustment is started, the dialysate stock solution injection pump is started at a constant initial flow rate. Step 2: When the concentration is out of the predetermined concentration range determined in advance, the flow rate of the dialysate undiluted solution injection pump is adjusted until the concentration measured by the chemical concentration sensor reaches the concentration range or further for a predetermined period thereafter. Run at the initial flow rate,
The concentration is quickly brought close to the target concentration so that the concentration reaches a predetermined concentration range, and after the above period has passed, the process proceeds to step 3.

Step 3: When the concentration is within the above range, the flow rate of the dialysate stock solution injection pump is changed according to the actual concentration measured by the chemical concentration sensor, and the flow rate is maintained for a predetermined period. Bring it closer to the target concentration. Alternatively, the density is adjusted until the density exceeds an allowable error with respect to a predetermined target density, and then step 3 is repeated. When the density is out of the density range, the process proceeds to step 2. Adjustment.

When the concentration is out of the predetermined concentration range, the dialysate stock solution injection pump is operated at a predetermined flow rate so that the concentration measured by the chemical concentration sensor is within the concentration range. The concentration of the dialysate solution injection pump is adjusted by the initial flow rate until it reaches the target value or further for a predetermined period thereafter, so that the concentration can be quickly brought close to the target concentration.

When the concentration is within the above-mentioned predetermined concentration range, the flow rate of the dialysate stock solution injection pump is changed so as to approach the target concentration by using the actual concentration measured by the chemical concentration sensor. The dialysate is maintained at its stable concentration with high accuracy because the flow rate is maintained and adjusted until a certain period of time elapses or until the concentration exceeds a predetermined target tolerance error. Can be made

In addition to the concentration of dialysate, the osmotic pressure,
In the case of adjusting the electric conductivity or the component ratio, the adjustment can be performed with the above configuration.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic system diagram of a personal dialysis apparatus using the dialysate concentration adjusting apparatus of the present invention. In the figure, 20 is the dialysate concentration adjusting apparatus of the present invention. The concentration adjusting device 20 of the present embodiment shows a case where two carbonate solutions, A stock solution and B stock solution, are diluted and mixed with water to prepare a bicarbonate dialysate.

In FIG. 1, 1 is a water supply line, 2 is a B stock solution supply line, 3 is an A stock solution supply line, 4 is a B stock solution injection pump, 5 is an A stock solution injection pump, 6 is a B solution mixing tank, and 7 is a solution A. Mixing tanks, 8 and 9 are concentration sensors, 10 is a liquid supply pump, 11 is a liquid supply line, 12 is a dialyzer, 13 is a bypass connector, 14 is a drainage pump, 15 is a drainage line, 16
Is a control unit.

The dialysate first forms a dialysate flow path by the bypass connector 13 and operates the A stock solution injection pump 5, the B stock solution injection pump 4, the feed pump 10, and the drainage pump 14. At this time, the B stock solution supplied from the B stock solution supply line 2 in the B solution mixing tank 6 is diluted and mixed with the water supplied from the water supply line 1 to prepare a B solution diluent, and then the A solution mixing tank 7 is further prepared. Then, the A stock solution supplied from the A stock solution supply line 3 is diluted and mixed with the B solution diluting solution to prepare a bicarbonate dialysate. The prepared bicarbonate dialysate is discharged by the feed pump 10 and the drainage pump 14 through the drain connector 15 via the bypass connector 13.

The concentration of the bicarbonate dialysate is adjusted by the flow rate of the feed pump 10, the A stock solution injection pump 5 and the B stock solution injection pump 4. That is,
The amounts of A stock solution and B stock solution are determined by the flow rate of the A stock solution injection pump 5 and the flow rate of the B stock solution injection pump 4, respectively, and the amount of water from the flow rate of the liquid supply pump 10 to the flow rate of the A stock solution injection pump 5 and the B stock solution injection. It is the amount obtained by subtracting the flow rate of the pump 4. Therefore, the concentration of the bicarbonate dialysate can be adjusted by controlling the flow rates of the feed liquid pump 10, the A stock solution injection pump 5, and the B stock solution injection pump 4. Generally, since the flow rate of the liquid supply pump 10 is controlled to be constant according to the patient's prescription, the concentration of the bicarbonate dialysate is adjusted by the flow rates of the A stock solution injection pump 5 and the B stock solution injection pump 4.

FIG. 2 is a concentration change curve of the bicarbonate dialysate when the present invention is applied. In the figure, the horizontal axis represents time and the vertical axis represents the concentration of the bicarbonate dialysate. First, when the concentration adjustment is started, for example, the liquid supply pump 10 is operated while being constantly controlled at 500 [ml / min], the B stock solution injection pump 4 is 18 [milliliter / minute], and the A stock solution injection pump 5 is 14 Operate with constant control of 3 [ml / min]. These flow rates are set in advance so that the concentration of the bicarbonate dialysate falls within the control range. The control range has a certain width and is preferably set to a value suitable for feedback control described later.

In this way, the concentration rises as shown by A in FIG. 2, and after about 1 minute, passes through the lower limit of the control range at point B and enters the control range. At this time, the stock solution B is stabilized in the state of C deviating from the target concentration unless the concentration is exactly adjusted according to the prescription. Time measurement is started at the time when the point B is passed, the concentration is measured by the concentration sensor 8 after, for example, 2 minutes, and feedback control is performed according to an instruction from the control unit 16 so that the dialysate approaches the target concentration. The feed rate of the B stock solution injection pump 4 is increased by the amount of the difference between and. The feedback control may be started within a predetermined period after reaching the control range as in the present embodiment, or may be started immediately after reaching the control range.

In this way, the concentration of the dialysate can easily reach the target concentration about 3 minutes after the start of concentration adjustment as shown by D. After that, if you repeat this operation every 2 minutes,
A bicarbonate dialysate stable to the target concentration can be obtained. Further, FIG. 3 is a density change curve when an error from the target density occurs when the density is stable. As described above, since the density correction operation is performed every 2 minutes, when an error from the target density due to a disturbance such as that shown at point E occurs, the error is corrected within 2 minutes as shown at point F. Is detected and the flow rate of the solution to be pumped by the B stock solution injection pump 4 is changed and maintained for a fixed time, in this case, 2 minutes, so that the concentration can be brought within an allowable error from the target concentration. In this case, it is possible to return to the target density as shown at the point G in about 1 minute.

Similarly, the concentration of the dialysate A stock solution is measured by the concentration sensor 9, and when the flow rate of the stock solution injection pump A is changed according to the instruction of the control unit 16, about 3 minutes after the start of the concentration adjustment, A stable bicarbonate dialysate can be adjusted to a target concentration. As described above, the dialysate can be rapidly prepared, the bypass connector 13 is released,
It is possible to supply the dialyser 12 with an accurately prepared dialysate. Further, even if the concentration of the dialysate changes, the concentration can be corrected promptly.

[0022]

When the concentration adjusting device of the present invention is used for diluting and mixing chemicals, the concentration can be stabilized quickly, so that the wasteful consumption of the stock solution is reduced, and the preparation operation time before using the device is reduced. Since the time is shortened, the economical effect is improved, and the waiting time for the work is shortened, so that the efficient operation of the device can be realized. Further, since the concentration of the drug solution can be stabilized at the target concentration, it is effective for adjusting the proper concentration in prescription.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of a hemodialysis apparatus using a concentration adjusting device of the present invention.

FIG. 2 is a diagram showing a density change curve at the start of density adjustment by the density adjusting apparatus of the present invention.

FIG. 3 is a diagram showing a concentration change curve when the concentration is stabilized by the concentration adjusting device of the present invention.

FIG. 4 is a diagram showing a density change curve at the start of density adjustment by a conventional density adjusting device.

FIG. 5 is a diagram showing a density change curve at the start of density adjustment by a conventional density adjusting device.

[Explanation of symbols]

 1 Liquid supply line 2 B liquid concentrate supply line 3 A liquid concentrate supply line 4 B liquid concentrate injection pump 5 A liquid concentrate injection pump 6 Liquid B mixing tank 7 Liquid A mixing tank 8 Concentration sensor 9 Concentration sensor 10 Liquid supply pump 11 Liquid supply line 12 Dialysis Device 13 bypass connector 14 drainage pump 15 drainage line 16 control unit 20 concentration adjusting device

Claims (1)

[Claims] 1. A water supply line, a dialysate stock solution supply line, a dialysate stock solution injection pump for sending a dialysate stock solution supplied from the dialysate stock solution supply line at a predetermined flow rate, and a supply line supplied from the water supply line. A mixing tank for diluting and mixing the dialysate stock solution supplied from the dialysate stock solution injection pump with water, a concentration sensor for measuring the concentration of the mixed chemical solution, and the dialysate stock solution and water. A dialysate concentration adjusting device comprising a supply pump for supplying dialysate to a dialyzer, and a control unit for receiving a signal from the concentration sensor and controlling the flow rate of the dialysate stock injection pump. Therefore, when the concentration is outside the predetermined concentration range determined in advance, until the concentration measured by the concentration sensor reaches within the predetermined concentration range determined in advance, or further for a predetermined period, The dialysate stock solution injection pump adjusts the concentration by a predetermined flow rate, and when the concentration is within the predetermined range, the dialysate stock solution is injected according to the concentration measured by the concentration sensor. A dialysate concentration adjusting device, wherein the concentration of the dialysate is adjusted by changing the flow rate of the pump.