JPH0155893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuously dissolving a sodium bicarbonate (NaHCO ₃ ) solution used in hemodialysis while adjusting its concentration.

Traditionally, acetate-based dialysate such as acetate, which is chemically stable and easy to handle, has been mainly used in hemodialysis, but in recent years, improvements in dialyzers have progressed, and the use of large-area dialysers has led to the use of acetate. Bicarbonate-based dialysis fluids have been reconsidered as more and more patients are experiencing so-called disequilibrium syndrome-like symptoms such as decreased blood pressure and nausea due to rapid transfer into the bloodstream.
It is effective in alleviating this symptom. However, during storage of concentrated sodium bicarbonate (NaHCO ₃ ) solutions, the concentration decreases due to the reaction 2NaHCO ₃ → Na ₂ CO ₃ + CO ₂ + H ₂ O, making storage impossible, and at the same time the pH increases, resulting in Ca ⁺⁺ When coexisting with , Mg ⁺⁺ , etc., carbonate is created and a precipitate is formed. Therefore, in order to supply a dialysate containing sodium bicarbonate, a bicarbonate-free solution whose pH has been adjusted in advance with hydrochloric acid etc. (hereinafter referred to as solution A) and a concentrated sodium bicarbonate solution (hereinafter referred to as solution B) are required. ) and 2 stock solutions must be mixed and diluted before use. This B solution decreases in concentration over time and cannot be stored, so it is complicated to manually dissolve the amount required for one dialysis each time it is used, and it is difficult to determine the concentration for each batch of solution. There are also differences in gender.

The following three methods are known as representative methods for preparing bicarbonate dialysate currently in use.

(1) Batch method A dialysate prepared by mixing and diluting liquid A, liquid B, and hot water at a fixed ratio is used in circulation.

(2) Metering pump method Using a metering pump, mix liquid A or B and water at a fixed ratio, mix this diluted liquid and liquid B or A at a fixed ratio, and measure the electrical conductivity of this liquid. is used to check the concentration of sodium bicarbonate in the dialysate.

(3) Bicarbonate solution injection method Mix and dilute solution A and warm water at a certain ratio, continuously inject solution B into the diluted solution A immediately before use, and measure the electrical conductivity of this solution to determine the weight of the dialysate. Checking sodium carbonate concentration.

In all methods (1), (2), and (3), the amount of concentrated sodium bicarbonate stock solution required for one dialysis treatment must be prepared in advance, and HCO ₃ ^-
It was also not possible to prevent the concentration from decreasing over time due to decomposition.

For this reason, method (1) intentionally ignores changes in dialysate over time and decreases in efficiency, and has too many problems. Methods (2) and (3) attempt to compensate for the decrease in the concentration of concentrated sodium bicarbonate stock solution by changing the mixing ratio during dialysate preparation, but HCO ₃ in the mixed and adjusted dialysate ^This concentration is extremely low compared to the concentration of other electrolyte ions, and it is difficult to accurately measure the concentration of HCO ₃ ^- due to the influence of other electrolyte ions, making it difficult to control the concentration. The problem was that it was difficult to perform accurately and that the concentrations of other electrolytes, including Na ⁺ , changed relative to each other.

All of the above-mentioned methods have the following problems, and the reproducibility of dialysate preparation is poor.

(1) Manpower is required to adjust the stock solution and control the concentration.

(2) Sensitive to decreases in HCO ₃ ^- concentration.

(3) It is difficult to supply dialysate with stable concentrations of each electrolyte.

Although bicarbonate dialysis is effective in improving imbalance syndrome-like symptoms, when the concentration decreases, there are concerns about problems such as ectopic calcification due to the formation of precipitates such as _CaCO3 .
Precise control of HCO ₃ ^- concentration is extremely important in the long term. As mentioned above, each of the conventional methods has many problems that need to be solved.

Therefore, the present invention dissolves sodium bicarbonate continuously and automatically, and supplies a sodium bicarbonate solution with a constant concentration that does not reduce efficiency over time to a dialysate supply device, which could not be done precisely in the past. The main object of the present invention is to provide a continuous sodium bicarbonate dissolving device that allows precise control of the HCO ₃ ^- concentration of the dialysate.

Another object of the present invention is to construct a dialysate supply device that continuously supplies sodium bicarbonate dialysate using a device that is simpler and more labor-saving than conventional devices, by combining with an existing acetic acid such as acetate or sodium bicarbonate mixing device. We are trying to provide a continuous sodium bicarbonate dissolution device that can be used to dissolve sodium bicarbonate.

According to the present invention, there is provided a sodium bicarbonate powder supply means, a water supply means with a control valve, a dilution tank for dissolving and mixing the supplied sodium bicarbonate powder and water, and measuring the concentration of the sodium bicarbonate solution in this tank. a first concentration measuring means for measuring the concentration of the sodium bicarbonate solution in the tank; a storage tank for storing the sodium bicarbonate solution for supply to the next step; a second concentration measuring means for measuring the concentration of the sodium bicarbonate solution in the tank; opening and closing the control valve of the means to operate the sodium bicarbonate powder supply means together with a predetermined amount of water to supply a predetermined amount of sodium bicarbonate according to the concentration of the sodium bicarbonate solution obtained from the first concentration measuring means; adjust the desired concentration of sodium bicarbonate solution by dispensing additional sodium bicarbonate powder or water by operating the control valve of the sodium bicarbonate powder supply means or water supply means, and then transfer it to the storage tank and dispense it again. 2. Automatically performs a concentration adjustment cycle configured to measure the concentration of the sodium bicarbonate solution using a concentration measuring means, determine whether the solution concentration is normal or abnormal based on the measured value, and decide whether to use or discard the sodium bicarbonate solution. A continuous sodium bicarbonate dissolving device is provided, comprising a sequence control means for controlling the continuous dissolution of sodium bicarbonate. The control valve of the water supply means is composed of solenoid valves for large-volume water supply and small-quantity water supply, and the dilution tank is equipped with a switch for supplying a predetermined amount of water and a lower limit level switch, and is configured to control these in sequence. do. Preferably, the storage tank is provided with a switch for sensing the level to be transferred from the dilution tank and a lower limit level switch for similar sequential control. In accordance with the present invention, means are provided to measure the concentration of the sodium bicarbonate solution in the storage tank to monitor whether the concentration is adequate and to determine whether the solution should be used or discarded. The sodium bicarbonate solution at the appropriate concentration stored in the storage tank is sequentially supplied to a conventional acetate or sodium bicarbonate two-liquid mixing device, and bicarbonate is produced by simply mixing it with other stock solutions at a fixed ratio without checking the concentration. Dialysate with constant sodium concentration can be supplied.

Next, the sodium bicarbonate continuous dissolving device of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

FIG. 1 diagrammatically shows the sodium bicarbonate dissolution apparatus of the present invention. The dilution tank 1 is supplied with sodium bicarbonate powder from a sodium bicarbonate powder supply means 2 and water from a water supply means 3. Powder supply control of the sodium bicarbonate powder supply means 2 is performed by controlling the rotation of a drum 5 having slits 4 as shown in FIG. 2, or by controlling the rotation of a screw conveyor 6 as shown in FIG. be exposed. That is, when it is necessary to initially supply a certain amount, it is driven to rotate a predetermined number of times at high speed, and when fine adjustment of the concentration is performed, it is driven at low speed. It is preferable that the sodium bicarbonate powder in the supply means 2 is prevented from absorbing moisture by a heater or the like, and that vibrations are applied to the supply means 2 so as not to cause a bridging phenomenon. The water supply means 3 is provided with solenoid valves V1 and V2 for large-volume supply and small-quantity supply in parallel, and when it is necessary to supply a certain amount of water first, the water volume is adjusted using a float switch or a flow meter (not shown). Measure V.
Water is supplied by appropriately switching and controlling V1 and V2.

A stirrer 7 is provided to completely dissolve the sodium bicarbonate powder fed into the dilution tank 1 to produce a homogeneous solution, and further forms a circulation circuit with the dilution tank 1 via lines 8 and 9. , a pump P1 is provided in the conduit 8, and a conductivity meter 10 is provided in the conduit 9 to form a circuit for measuring the concentration of the sodium bicarbonate solution in the dilution tank. The dilution tank 1 is first provided with a variable level switch S1 and a lower limit level switch S2 for supplying a predetermined amount of water, and float switches are preferred as these switches are highly reliable. The lower limit level switch is to prevent the sodium bicarbonate solution from foaming abnormally and stirring.

The line 8 is connected to a storage tank 11 via a solenoid valve V3, from which a sodium bicarbonate solution of a desired concentration is supplied via a line 12 to the next dialysate production step via a pump P2 and a solenoid valve V4. .
As shown in FIG. 1, it is preferable that a concentration measuring circuit is also formed in the storage tank 11 via a conduit 15 having a pump P2 on a conduit 12, a conductivity meter 13, and a check valve 14. When the sodium bicarbonate solution in the storage tank 11 has an appropriate concentration, it is supplied to the next step as described above, and when the concentration is abnormal, it is discharged through the drain pipe 16.

As mentioned above, concentration measuring means are provided in each of the dilution tank and the storage tank, and the concentration is checked twice by these means, so that the concentration of the sodium bicarbonate solution can be controlled more precisely.

The storage tank 11 is equipped with a lower limit level switch S4.
Furthermore, a level switch S3 is provided for opening the valve V3 and transferring the sodium bicarbonate solution from the dilution tank 1 when the level drops to S3 during supply of the sodium bicarbonate solution. Float switches are also preferable for these switches. Therefore, it is necessary to set the position of the switch S3 at such a position that the dilution tank 1 can contain at least as much solution as the volume of the switches S1 to S2.

Next, the sequence control method of the continuous sodium bicarbonate dissolving apparatus according to the present invention will be explained with reference to the flowchart shown in FIG.

When the start button for producing a sodium bicarbonate solution is pressed, sodium bicarbonate powder is supplied from the sodium bicarbonate powder supply means 2, and water is supplied to the dilution tank 1 in a predetermined amount from the water supply means 2 by opening the solenoid valve V1. Supplied up to S1 level. When the level of S1 is reached, the supply means 2 are stopped and V1 is closed. At the same time, the stirring means 7 is activated, and the pump P1 is activated with V3 closed to circulate the sodium bicarbonate solution through the conductivity meter 10 until the rate of change in concentration measured moment by moment is below a certain value. If the concentration of the sodium bicarbonate solution in the dilution tank 1 is higher than the target concentration based on the concentration measurement result when the water is supplied or after a certain period of time has elapsed after water supply, the solenoid valve V2 is opened to dispense the required amount of water. Note that if the concentration is lower than the target concentration, the supply means 2 is activated to supply the required amount of sodium bicarbonate powder. The concentration is checked again as described above, and when the target concentration is finally reached, the solenoid valve V3 is opened and the sodium bicarbonate solution is transferred to the storage tank 11 up to the level of the switch S2 in the dilution tank 1. Valve V3 is then closed. Sodium bicarbonate powder and water are then supplied to the dilution tank 1 again in the order described above to produce a sodium bicarbonate solution with a desired concentration.

The sodium bicarbonate solution in the storage tank 11 is stirred to make the concentration homogeneous by the operation of the pump P2, and the concentration is checked by the conductivity meter 13. If there is no abnormality in the concentration, the solenoid valve V4 is opened. If there is an abnormality, solenoid valve V4 is closed and drain 1 is supplied to the next dialysate generation process.
6 and then discarded.

While being supplied from the storage tank 11 to the next process, a sodium bicarbonate solution of a desired concentration is generated in the dilution tank 1 and is waiting there. When the level in the storage tank 11 drops to S3, the solenoid valve V3 is opened and the solution in the dilution tank 1 up to the level S2 is transferred to the storage tank 11. Such cycles occur continuously and automatically. Note that if the amount of solution in the storage tank 11 is too small, the concentration tends to change greatly, so when the level drops to the position of the switch S4, the valve V4 is closed.

As is clear from the above explanation, the sodium bicarbonate continuous dissolving device of the present invention brings about many effects as described below.

(1) In conventional sodium bicarbonate dialysis equipment, the user dissolves and adjusts the concentrated stock solution of sodium bicarbonate in the amount necessary for dialysis at the time of use, but this is very labor-intensive and prone to errors. However, since a dialysate with a stable concentration is supplied, these problems are resolved and it is possible to achieve safety and significant labor savings.

(2) Since the concentration of HCO ₃ ^- is adjusted continuously and automatically using a dedicated concentration measuring device without relying on human hands, it is possible to prevent changes in sodium bicarbonate stock solution over time and decrease in efficiency over time, unlike in the past. It never comes.

(3) The device of the present invention can be used in combination with a conventional two-liquid mixing device, resulting in a dialysate adjustment system that is more reliable than the conventional device.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the sodium bicarbonate continuous dissolving device of the present invention, Figs. 2 and 3 are diagrams of a configuration example of the sodium bicarbonate powder supply means, and Fig. 4 is a sequence control system of the device of the present invention. This is a flowchart. Explanation of symbols, 1... Dilution tank, 2... Sodium bicarbonate powder supply means, 3... Water supply means, 4...
...Slit, 5...Drum, 6...Screw conveyor, 7...Stirring means, 8, 9, 12, 15...
... Pipe line, 10, 13 ... Conductivity meter, 11 ... Storage tank.

Claims (1)

[Claims] 1. A sodium bicarbonate powder supply means, a water supply means with a control valve, a dilution tank for dissolving and mixing the supplied sodium bicarbonate powder and water, and a method for controlling the concentration of the sodium bicarbonate solution in this tank. The first thing to measure
concentration measuring means, a storage tank for storing the sodium bicarbonate solution for supply to the next step, second concentration measuring means for measuring the concentration of the sodium bicarbonate solution in the tank, and said water supply means for said dilution tank. by opening and closing the control valve to operate the supply means together with a predetermined amount of water to supply a predetermined amount of sodium bicarbonate to the dilution tank, so that the concentration of the sodium bicarbonate solution obtained from the first concentration measuring means is adjusted to Adjust the sodium bicarbonate solution of the desired concentration by dispensing additional sodium bicarbonate powder or water by operating the control valve of the sodium bicarbonate powder supply means or the water supply means accordingly, and transfer this to a storage tank. The concentration is configured to measure the concentration of the sodium bicarbonate solution again by the second concentration measuring means, determine whether the solution concentration is normal or abnormal based on the measured value, and decide whether to use or discard the sodium bicarbonate solution. A continuous sodium bicarbonate dissolving device, characterized in that it comprises sequence control means for controlling automatic adjustment cycles. 2. The continuous sodium bicarbonate dissolving device according to claim 1, wherein the control valve of the water supply means is comprised of a large-capacity supply solenoid valve and a small-volume supply solenoid valve. 3. The continuous sodium bicarbonate dissolving device according to claim 1 or 2, characterized in that a predetermined amount setting level switch and a lower limit level switch are provided in the dilution tank. 4. Sodium bicarbonate according to any one of claims 1 to 3, wherein the storage tank is provided with a switch for sensing the level to be transferred from the dilution tank and a lower limit level switch. Continuous melting equipment.