JPS649586B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dispensing device for dispensing a liquid sample such as serum, and particularly to an improvement in a washing and drying mechanism for a dispensing nozzle.

When dispensing a sample liquid such as serum, inserting multiple nozzles into the liquid sample to aspirate it, then simultaneously pulling up each nozzle and inserting it into multiple dispensing tubes to discharge it improves dispensing ability. However, when dispensing serum, etc. from different patients one after another, the nozzle must be washed and dried each time.
For example, when handling serum from different patients, distilled water or ion-exchanged water is flushed through the nozzle to clean it, and then compressed air is blown into the nozzle to dry it. Problems have arisen, such as water being sprayed in fine particles from the nozzle tip by compressed air and wetting the surrounding area, and water droplets from the nozzle tip being difficult to remove. Also,
It is very difficult to completely remove water droplets from the tip of the nozzle, and according to experimental results, the water droplets could not be completely removed unless air pressurized to 3 kg/cm ² was flowed for 15 seconds or more.

Forcibly removing water droplets using compressed air or the like as described above is not a suitable method because the water droplets are likely to spread and contaminate nearby containers. Therefore, when cleaning the inside of a tube or nozzle, a method is used in which water is allowed to flow down naturally using its own weight. However, this method also has the following problems, and unless these problems are solved, reliable washing and drying cannot be performed.

(1) If the water inside the tube or nozzle is allowed to flow down naturally, negative pressure will develop inside the tube, which will gradually make it difficult for water to flow down and the cleaning ability will decline.

(2) If the height of the water surface in multiple tubes or nozzles is different, the force of the water flowing down will be different, and the longer the water column will fall in a larger amount. The negative pressure generated by this pulls up water droplets in other tubes and nozzles with which they are communicated, causing them to flow back inside the tube. This phenomenon also occurs when the internal diameters of the nozzles and tubes are different and there is a difference in volume, and in the worst case, the air enters the air suction and discharge pump through the air path, making its operation unsmooth.

The present invention aims to eliminate the drawbacks of the prior art and provide a dispensing device that can quickly and reliably clean and dry the inside of multiple nozzles and tubes.
The feature is that an atmospheric pressure introduction means is installed in the air path connected to the compressed air source, and when washing the nozzle, outside air is introduced into the air path through the atmospheric pressure introduction means, and the inside of the nozzle is The reason is that the cleaning water is constructed so that it flows out under its own weight.

The present invention was made based on the results of examining the cause of poor water drainage when cleaning conventional nozzles, and confirming that the cause was that the air passages communicating with multiple nozzles were in a closed circuit system. It is something that

FIG. 1 is a system diagram of a dispensing device that is an embodiment of the present invention. The nozzle 1 is connected to a three-way switching valve 12 via a tube 4, the nozzle 2 is connected to a three-way switching valve 13 via a tube 5, and the nozzle 3 is connected to a three-way switching valve 14 via a tube 6. The three-way switching valves 12, 13, and 14 communicate with the waterway and the air passage, respectively, and each air passage is connected to the three-way switching valve 15, 1.
6 and 17, respectively. Further, each of the three-way switching valves 15, 16, and 17 communicates with an air compressor 22 via a three-way switching valve 21, and the three-way switching valve 15 communicates with an air pump 18, and the three-way switching valve 16 communicates with an air pump 19. The three-way switching valves 17 are respectively connected to air pumps 20. Note that 7 is a sample tube, 8, 9, and 10 are dispensing tubes, and 11 is a washing tank.

The outline of the dispensing operation of this dispensing device will be explained below. The nozzles 1 to 3 that have been washed and dried are simultaneously moved onto the sample tube 7 by the dispensing mechanism and lowered, and their lower ends are inserted into the sample liquid. At this time, the three-way switching valves 12 to 14 and the three-way switching valves 15 to 17 are all connected in the direction of the broken line arrow in the figure, so if the pistons of the air suction and discharge pumps 18 to 20 are simultaneously moved and sucked by the same distance, ,
Equal amounts of sample liquid are drawn into the nozzles 1-3. Next, when the three nozzles 1 to 3 are pulled up and moved onto the dispensing tubes 8, 9, and 10, and the pistons of the air suction and discharge pumps 18 to 20 are raised, each of the dispensing tubes 8 to 10 is An equal volume of sample solution is dispensed.

In this way, when dispensing the same sample solution again, the same operation as above can be repeated to dispense the sample solution into more dispensing tubes, but if a different sample, for example serum from a different patient, is dispensed. In this case, the following cleaning and drying operations are required.

At this time, the nozzles 1 to 3 are moved above the cleaning tank 11 and lowered a little, and the tips of the nozzles 1 to 3 are housed in the cleaning tank 11. After that, the flow paths of the three-way switching valves 12 to 14 are connected to the side of the solid line arrow, and the cleaning water is passed through the tubes 4 to 6 and the nozzles 1 to 3.
Clean the inside gently. At this time, the surrounding environment is prevented from being contaminated by splashing of the washing water, which is allowed to flow down naturally from the washing water storage tank.

Next, we will start drying the insides of nozzles 1 to 3 and tubes 4 to 6, but at this time we will dry the insides of three-way switching valves 12 to
14 in the direction of the dashed arrow, the three-way switching valves 15 to 17
Switch in the direction of the solid arrow. Further, the three-way switching valve 21 is set in the direction of the broken line arrow to communicate the atmosphere with the air passage. Therefore, all of the nozzles 1 to 3 are at atmospheric pressure, and the cleaning water therein naturally flows down due to its own weight. At this time, water droplets adhering to the inside of the pipe are collected, so no water droplets remain inside the pipe. Also, nozzle 1
A small amount of cleaning water remaining at the tip of 3 can be easily and completely removed by switching the flow path of the three-way switching valve 21 to the side indicated by the solid line arrow and allowing the compressed air from the air compressor 22 to pass through. After being discharged, the insides of nozzles 1 to 3 and tubes 4 to 6 are quickly dried.

In addition, since nozzles 1 to 3 use small diameter pipes made of stainless steel, there is generally little wetting by the liquid, but
The sample liquid adhering to the outside is washed away by spraying cleaning water. After cleaning and drying the inside and outside of the nozzles 1 to 3 and the insides of the tubes 4 to 6 in this manner, the three-way switching valves 15 to 17 are switched to the side indicated by the dashed arrow to communicate with the air suction and discharge pumps 18 to 20,
The process moves on to dispensing the sample solution again.

The dispensing device of this embodiment has a three-way switching valve installed in the pressurized air flow path of the air compressor, and is configured to introduce air into the tube and nozzle after cleaning the nozzle, thereby cleaning the inside of the nozzle. The water flows down under its own weight so that only a small amount remains at the tip of the nozzle, and when the next time compressed air is introduced, these water droplets can be discharged to quickly dry the inside of the nozzle or tube. This has the effect of improving the reliability and efficiency of dispensing work.

On the other hand, conventionally, the three-way switching valve 21 was not provided and the air compressor 22 was directly connected.
Before the air compressor 22 was activated, the nozzles 1 to 3 were in communication with a sealed air path. Therefore, when the amount of cleaning water remaining in nozzle 1 is large and the amount of residual cleaning water in nozzles 2 and 3 is small, when the cleaning water in nozzle 1 flows down, negative pressure is generated and other The residual water in the nozzles 2 and 3 is raised to equalize the pressure in the air passage system.
The cleaning water rising at this time is
4, 16, and 17 into the air passage, and in extreme cases could even enter the air suction and discharge pump 18 and air compressor 22.

When this happens, the air suction and discharge pumps 19-2
When the air compressor 22 is operated, backflowing cleaning water is intermittently spouted and scattered from the nozzles 1 to 3, contaminating the vicinity thereof. These drawbacks can be overcome by installing the three-way switching valve 21 in the air path immediately after the air compressor 22, as described above.

FIG. 2 is an explanatory diagram of the main parts of the air passage which is a modification of FIG.
4 is used to perform the same function as the three-way switching valve 21 shown in FIG. The figure shows a state in which compressed air is being supplied from the air compressor 22. At this time, the two-way switching valve 23 is moved left and right to communicate with the check valve 24.
is closed because high pressure is on the ball side. When dispensing a sample liquid after drying the inside of the nozzle in this state, the two-way switching valve 23 is moved to the left to close the flow path. At this time, the ball of the check valve 24 becomes free and introduces air into the air passage system, releasing the negative pressure state. Therefore, nozzle 1~
The remaining amount of the cleaning liquid in the valve 3 when it flows down by gravity is only a small amount remaining at the tip of the nozzle, and the same effect as the three-way switching valve 21 in FIG. 1 can be obtained.

The two-way switching valve and check valve of this embodiment provide the same effect as when the three-way switching valve shown in FIG. 1 is installed in the pressurized air path of an air compressor.

The dispensing device of the present invention has a simple improvement in that it includes an atmospheric pressure introducing means that can introduce atmospheric pressure into the pressurized air path which is the downstream side of the air compressor of the conventional cleaning/drying mechanism. Also, the efficiency and reliability of the tube cleaning and drying work can be improved.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a dispensing device that is an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the main part of an air passage that is a modification of FIG. 1. 1-3...nozzle, 4-6...tube, 7...
...Sample tube, 8-10...Dispensing tube, 11...Washing tank, 12-17, 21...Three-way switching valve, 18
~20... Air suction and discharge pump, 22... Air compressor, 23... Two-way switching valve, 24... Check valve.

Claims (1)

[Scope of Claims] 1. A dispensing device that has a plurality of nozzles for simultaneously collecting and distributing a sample liquid, and that uses compressed air after washing the nozzles with water and then passing and drying the compressed air, wherein the source of the compressed air is An atmospheric pressure introduction means is installed in the air passage connected to the nozzle, and when washing the nozzle with water, outside air is introduced into the air passage through the atmospheric pressure introduction means, so that the washing water in the nozzle flows out under its own weight. A dispensing device characterized by comprising: 2. Dispensing according to claim 1, wherein the atmospheric pressure introducing means is a three-way switching valve connected to the source of the compressed air or the atmospheric side and the air path communicating with the plurality of nozzles. Device. 3. The atmospheric pressure introduction means includes a two-way switching valve connected to the compressed air source and the air passage communicating with the plurality of nozzles, and a reverse valve installed between the air passage and the atmosphere side. The dispensing device according to claim 1, which is a stop valve.