JPS624140B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for degassing dialysate for an artificial kidney.

An artificial kidney is a dialysis device for removing harmful metabolic products and water from the blood by mass transfer between the blood side and the dialysate side separated by a semipermeable membrane. The dialysate has a chemical composition that approximates as closely as possible that of the components in normal blood water to prevent essential electrolytes from being lost from the blood through dialysis. Therefore, the dialysate is prepared on the spot by diluting a solution containing the above-mentioned essential electrolytes at a high concentration, called a stock solution, with tap water or the like, and is continuously supplied to the flow path within the dialyzer.

It is desirable that the dialysate fluid be at a temperature as close as possible to the patient's body temperature, so the water used is heated to body temperature or slightly higher with a heater prior to or after mixing with the stock solution.

Also, in some types of dialyzers, such as hollow fiber or plate types, the removal of excess water from the blood, called ultrafiltration, involves suctioning the dialysate downstream of the dialyzer. It uses the principle of generating negative pressure below atmospheric pressure and moving water molecules from the blood side to the dialysate side through a membrane due to the pressure difference with the blood side.

As is well known, the solubility of a gas in a liquid is inversely proportional to the temperature of the liquid and directly proportional to the partial pressure of the gas. Therefore, the above-mentioned situation is consistent with the condition that the solubility of air and other gases dissolved in the dialysate or the dilution water used to prepare it is low, and if no degassing treatment is performed, Not only do they become bubbles and flow through the flow path with the dialysate, reducing the efficiency of dialysis, but if they enter the bloodstream, they can be introduced into the patient's body, resulting in serious consequences. Therefore, the dialysate, or the water for its preparation, is preferably degassed before entering the flow path in the dialyzer.

The present invention is relatively simple in structure, efficient, and
Moreover, it is an object of the present invention to provide a degassing system for the above-mentioned purpose that is flexible with respect to the flow rate of the liquid to be treated.

The degassing system of the present invention includes a negative pressure control valve, a negative pressure control valve, a negative pressure control valve, a negative pressure control valve, a negative pressure control valve, and a negative pressure control valve, from upstream to downstream, from the dialysate diluted with water, or water before being mixed with the stock solution, to the main flow path of the liquid to be treated. pressure accumulator tank,
A pump for generating a negative pressure in the main flow path between the negative pressure control valve including the accumulator tank, and a gas separation tank having a means for exhausting the separated gas at the upper part are arranged in series in the stated order. and a reflux circuit for deaerated liquid to be treated, which is arranged in parallel to the main flow path, and further connects the separation tank to a confluence point with the main flow path located upstream of the negative pressure control valve. It is characterized by having the following.

The pump is operated at a constant speed and at a constant flow rate, such that the flow rate of the liquid to be treated through the pump is at least as high as the flow rate of fresh liquid to be treated through the main channel which is combined with the liquid to be treated returning at the junction point. Preferably, it is twice as large. Therefore, the fresh liquid to be treated passes at least twice through the accumulator tank and the gas separation tank, which are arranged in series in the main flow path, and is thoroughly degassed before being sent to the dialyzer.

The present invention will be described in further detail with reference to the drawings, which are preferred embodiments of the present invention.

The main flow path includes a portion 10 into which a liquid to be treated heated by a heater is introduced, a negative pressure control valve 12, an accumulator tank 14, a pump 16, and a separation tank 1.
8 in series, and a section 13 that sends the degassed treatment liquid from the separation tank to the dialyzer.
It consists of. The stock solution is supplied to the upstream portion 10 of the main channel.
to be mixed further upstream of the heater or mixed into the main flow path in the downstream section 13.
The liquid to be treated supplied from the main flow path section 10 enters the section 11, first passes through the negative pressure control valve 12, and then enters the negative pressure accumulator tank 14. pump 16
sucks a certain amount of liquid to be treated at a constant speed, thereby generating a negative pressure between the valve 12 of the flow path 11 including the accumulator tank 14 and the pump 16.

Therefore, after the liquid to be treated passes through the valve 12, the gas dissolved inside is liberated and becomes a large number of small bubbles.
Enter the accumulator tank 14. The tank 1
4 has a cross-sectional area that is sufficient to reduce the linear velocity of the flow of the liquid to be treated flowing through it, promote the generation of bubbles by negative pressure with sufficient residence time, and grow them into large bubbles that are easy to separate. and height. After the accumulator tank 14, the liquid to be treated is sent into the gas separation tank 18 by a pump 16 while containing the grown bubbles. The tank 18 has an exhaust pipe 22 projecting from the inside of the tank to the outside at its upper part, and is equipped with a spherical float 24 that comes into contact with the lower edge of the exhaust pipe 22 to close it off. Therefore, while the float is at a height that does not block the exhaust pipe 22, air bubbles in the liquid to be treated that are sent by the pump 16 float in the tank 18 and are discharged from the exhaust pipe 22 into the atmosphere. Ru. The degassed liquid moves to the opposite side over the partition wall 26 in the tank, a part of which is discharged via the main channel 13 to the dialyzer, and the remainder passes through the reflux channel 19 and reaches the confluence point 20. Return to the main flow path 11. pumping capacity of the pump 16;
That is, the flow rate of the liquid to be treated passing through the portion 11 of the main flow path
Q ₂ must be greater than the flow rate Q ₁ of the liquid freshly introduced into this circuit from the channel 10 (which is equal to the flow rate Q ₃ of the liquid sent from the separation tank 18 via the channel 13 to the dialyzer). Of course, it is preferable that the flow rate is at least twice the flow rate _Q1 . As a result, the liquid supplied from the flow path 10 passes through the degassing circuit consisting of the accumulator tank 14, the pump 16, and the separation tank 18 at least twice, and the air bubbles in the accumulator tank 14 are eliminated. After being sufficiently degassed to promote growth, it is sent to the dialyzer via the flow path 13.

The system of the present invention has a feature that it can cope with fluctuations in the flow rate Q ₃ of the degassed dialysate sent from the flow path 13 to the dialyzer without reducing its efficiency. That is, the flow rate Q ₂ of the liquid through the valve 12, the tank 14, the pump 16 and the separation tank 18 which constitute the degassing circuit is constant and is greater than the flow rate Q ₃ of the liquid supplied from the separation tank to the dialyzer. Therefore, the difference Q ₂ -Q ₃ is returned to the upstream side of the degassing circuit at the junction 20 through the reflux path 19. Therefore, if the amount Q ₃ of fluid supplied to the dialyzer becomes smaller, the amount of fluid refluxed increases accordingly, and the amount Q ₁ of fluid newly taken in from the flow path 10 decreases accordingly. Since the confluence point 20 of the refluxing liquid is located upstream of the valve 12, the flow rate Q ₂ of the main flow portion 11 is
does not change, and the negative pressure generated between the valve 20 and the pump 16 also does not change. Furthermore, as the flow rate Q ₃ of the liquid supplied from the flow path section 13 to the dialyzer increases, the flow rate of reflux becomes smaller accordingly, and the newly taken in liquid amount Q ₁ also increases correspondingly. However, since the negative pressure between the valve 12 and the pump 16 and the flow rate Q ₂ remain constant despite variations in the new liquid flow rate Q ₁ entering the system and the liquid flow rate leaving the system Q ₃ . , the above-mentioned efficient degassing process is always performed. The mounting position of the reflux path 19 to the separation tank 18 is the partition wall 26.
This is the side opposite to the main flow path 11 from the polp 16 with respect to the main flow path 11 . As a result, air bubbles float to the surface and the separated liquid to be treated flows back, and the partition wall prevents air bubbles from being mixed into the liquid exiting from the flow path 13 sent to the dialyzer. The float valve 24 is connected to the separation tank 18
This prevents the water level from rising and overflowing from the exhaust pipe 22. As the water level falls and the float 24 moves away from the lower edge of the tube 22, it allows the gas separated from the tube 22 to escape to the atmosphere.

The system of the present invention can be equipped with conventional meters at appropriate locations. For example, a pressure gauge 22 can be installed in the main channel section 11, intermediate the valve 12 and the accumulator tank 14, in order to measure and monitor the negative pressure at this point.

As described above, the deaeration system of the present invention has a relatively simple structure, which reduces the occurrence of failures.
On the other hand, the degassing efficiency is further improved, and it has the advantage of being able to withstand fluctuations in the flow rate of the liquid to be treated without reducing the efficiency.

[Brief explanation of the drawing]

The drawing is a circuit diagram of the air system of the present invention. 10, 11, and 13 are main channels, 12 is a negative pressure control valve, 14 is an accumulator tank, 16 is a pump, 18 is a separation tank, and 19 is a reflux circuit for the liquid to be treated.

Claims (1)

[Claims] 1 In a system for degassing gas dissolved in a treated liquid consisting of water before being mixed with a dialysate stock solution or dialysate after being mixed with a stock solution, a main channel through which the processed liquid flows, leading to a dialyzer. a negative pressure control valve, a negative pressure accumulator tank, and a pump for generating negative pressure in the main flow path between the negative pressure control valve including the accumulator tank from upstream to downstream; , gas separation tanks having separated gas evacuation means at the upper part are arranged in series in the stated order, and further a connection point between the separation tanks and the main flow path located upstream of the negative pressure control valve. The system further comprises a reflux circuit for a degassed liquid to be treated, which is arranged in parallel with the main flow path connecting between the main flow channels.