JPH0342376Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a liquid dispensing device that injects a predetermined amount of water such as a diluent into test tubes arranged in a plurality of test tube racks. The present invention relates to a liquid dispensing device that enables uniform dispensing of water at any time and eliminates so-called dripping.

[Conventional technology and problems]

In this type of device, a desired reaction is observed by adding a fixed amount of water or a predetermined reagent to test tubes containing different samples, so the amount of fluid placed in each test tube must be constant. The conventional device consists of one tank connected to a water pump and a plurality of water injection nozzles installed vertically below this tank.As long as the water pressure is constant, the amount of water or liquid injected will be constant. As seen in simple devices created based on this assumption and Utility Model Application No. 57-137729 (name of invention: quantitative water dispensing device), the inside of the tank is sealed and air pressure is used to There is a method that maintains the water at a constant pressure and uses air pressure to dispense a fixed amount using an opening/closing plate that synchronously opens the opening end of the water injection nozzle facing into the tank.

However, the latter device requires a mechanism to open and close the nozzle opening at the same time in the tank, which poses problems in terms of manufacturing cost and service life.Also, although the former device has a simple configuration, in reality, each test There is a drawback that it is not possible to accurately dispense a fixed amount into a tube.

After many years of research into the cause, the inventor discovered that the air that happens to be included in the water supply randomly sticks to the ceiling of the tank as bubbles, and even when water is being supplied, these bubbles remain in the same position and are not affected by the flow of water. I noticed that it was not affected that much and the range of movement was limited.

If such air bubbles stick to the top surface, even if the flow pressure and water delivery time are constant, the presence of air bubbles will cause a difference in the resistance in each flow path, and this will result in a difference in the amount of water injected from each water injection nozzle. I found out that it appears as a difference. Furthermore, if air bubbles are present, water droplets will inadvertently drip from the water injection nozzle when water is not being poured due to expansion and contraction of the bubbles, which also becomes a factor that inhibits quantitative water injection.

Such bubbles cannot be easily removed even if the flow of water during water supply is strengthened. This is because the bubble moves to the top plate due to its buoyancy, receives three reaction forces from the top surface, and deforms into a flat shape.As a result, the bubble and the top surface stick together with a large contact area, and the contact resistance is quite strong. This is because it is a thing.

[Means for solving problems]

This invention attempts to solve the problems caused by the above-mentioned phenomena inside the tank, and its purpose is to maintain a constant amount of water dispensed from one tank or chamber to the water injection nozzle. The gist is that in a liquid dispensing device that has one chamber communicating with a water injection pump and a plurality of water injection nozzles that communicate with this chamber and are installed vertically below the water injection nozzle. The periphery of the top surface of the chamber on the upward extension line is a recess that widens downward, and the upper opening of the water injection nozzle is located within this recess. .

The liquid to be dispensed in the present invention may include a solution containing a reagent, water for washing, or any other liquid that can be dispensed in a fixed amount. Also,
The dispensing device includes not only one that dispenses liquid by itself, but also partially applies to a dilution cleaning device that dispenses liquid and sucks out the dispensed water. In other words, in the dilution cleaning device,
Although a water injection system and a water absorption system are provided in combination, if we focus on the water injection system, it can be said to be a dispensing device.

This dispensing device has one chamber that communicates with a water pump and a plurality of water injection nozzles that are vertically installed directly below the chamber. The entire water injection nozzle may be able to move up and down, but it may also be fixed and the platform on which the test tube rack is placed may be moved up and down. Communication between the water pump and the chamber is usually achieved through pipes. If possible, the pipe itself may be used as a member constituting the chamber, but usually a tank or tank is connected to the pipe, and the interior thereof becomes the chamber. In this room,
The vertically installed water injection nozzle below it is in communication.
The water injection nozzle is a hollow cylinder, and in dilution cleaning equipment, the water injection nozzle and the suction nozzle are connected in parallel, or the water injection nozzle is provided concentrically outside the water absorption nozzle, giving the appearance of a composite pipe. Even in this case, the water injection pipe is included in the water injection nozzle of the present invention.

The upper end of the water injection nozzle faces the chamber, and the top surface extending upward is a recess that spreads downward, and the opening of the water injection nozzle is located within the recess.

The recess has a downwardly expanding shape and a semicircular cross section.
This includes any shape such as a mountain-shaped cross section, but the angle of inclination does not matter. However, it is preferable to make the recess large and to minimize the flat portion on the top of the chamber. For example, the top surface may be formed into a continuous saw shape.

On the other hand, the upper opening of the water injection nozzle is located in the recess, but it is sufficient that the opening of the water injection nozzle communicates with the chamber in any form, such as by burying its upper end in the ceiling. If it is necessary to securely support the water injection nozzle, a slit may be provided below the opening end, and this slit at the upper end of the water injection nozzle may be used as an upper opening to face into the recess. Of course,
At the same time, the upper opening may be a window such as a round window or a square window.

[Effect]

Since the present invention is constructed as described above, each water injection nozzle is inserted in advance into a test tube that is easily mounted using an elevating device, and then the water pump is driven. Initially, the chamber and nozzle are filled with water in advance. When water is sent by the water pump in this state, the water that has remained in the chamber and nozzles passes through each nozzle and is dispensed into the test tubes. When the dispensing process is completed, while repeating this process of pulling up the water injection nozzle, if air bubbles enter the chamber, they may stick to the top of the chamber in a flat state, but the opening of each water injection nozzle in the chamber Since a concave area is formed around the concave area that expands downward, the bubbles move to some extent due to fluid pressure and natural circulation pressure, and when they reach the edge of the concave area, their buoyancy causes them to float up the internal wall of the concave area. Then, the water is discharged to the outside from the opening of the water injection nozzle, and the room is degassed. As a result, when the water pump is stopped, the room is filled with liquid.

〔Example〕

1 is a liquid dispensing and absorbing device including the device according to the present invention, and 2 is a stand on which a rack 4 loaded with test tubes 3 is placed, which is slightly inclined rearward. Although only five test tubes 3 are shown in the figure, they are similarly arranged in several rows in the depth direction of the figure. Reference numeral 5 designates a nozzle whose tip is positioned directly above each test tube 3 and is vertically installed below the tank 6.

The tank 6 has two upper and lower chambers, the first chamber 7 being a water injection chamber, and the second chamber 8 being a water absorption chamber.

The nozzle 5 is a double pipe, and the inner nozzle is a water absorption nozzle 9 that penetrates the lower first chamber 7.
An upper opening 10 faces the second chamber 8. 1
1 is a water injection nozzle arranged concentrically with a gap provided around the water absorption nozzle 9. Around the top surface 12 of the first chamber 7 through which the nozzle 5 passes, there is formed a recess 13 with a mountain-shaped cross section that expands downward, and the upper end of the water injection nozzle 11 is embedded in the center of the recess 13. A slit 14 formed at the edge of the opening is located within the chevron-shaped recess 13, and the first chamber 7 and the water injection nozzle 11 communicate with each other. In FIG. 4, the top surface of the first chamber 7 is serrated. The water injection nozzle 11 has a spacer 1 slightly above the tip of the water absorption nozzle 9.
5 to the water absorption nozzle 9, and the spacer 1
It opens to the outside through a slit 16 provided in 5.

17 is the first chamber 7 and a water pump (not shown)
A pipe 18 connects the second chamber 8 and a water suction pump (not shown).

Reference numeral 19 denotes a holding plate that holds each tank 6 at its rear end, and this holding plate 9 is supported above the rail 20 to fixedly support the plurality of tanks 6 as a whole. The stand 2 is connected to the rail 2 via the support plate 21 and the ring.
0, and can be raised and lowered by rotating the rail 20 with the driving force of the motor 22. 23 and 24 are stoppers that determine the upper and lower limit positions of the platform 2.

〔effect〕

As mentioned above, in the present invention, a concavity that spreads downward is formed around the top of the chamber on the upward extension of the water injection nozzle, so that air bubbles contained in the water flow can reach the top. Even if the bubbles are stuck, a slight movement due to fluid pressure or other external force causes the bubbles to climb up the inner wall of the recess due to their buoyancy, and are degassed to the outside through the upper opening of the water injection nozzle. As a result, the room is kept as free from air bubbles as possible, the room is always filled with water, and the water injected from the water injection nozzle flows out extremely smoothly without being obstructed by air bubbles, improving the accuracy of quantitative water injection. It was possible to do that.

In addition, if air bubbles remain in the room, water droplets will occur even when water supply is stopped due to changes in the volume of the air bubbles, but in this invention, by adopting the above configuration, the air bubbles are collected in the recess. Since the chamber is deaerated and there are no air bubbles in the chamber, it is possible to prevent unexpected water droplets from dripping, and in this respect as well, highly accurate quantitative outflow can be performed.

[Brief explanation of the drawing]

The drawings show a liquid dispensing and absorbing device including the device according to the present invention, FIG. 1 is an enlarged sectional view of the tack and nozzle, FIG. 2 is a partially sectional side view of the entire device, and FIG. FIG. 4 is an enlarged cross-sectional view of the connecting portion between the water injection nozzle and the first chamber, FIG. 4 is a cross-sectional view showing another embodiment of the top recess, and FIG. The enlarged sectional view shown in FIG. 6 is a perspective view of the spacer. 2... stand, 3... test tube, 4... easy, 5...
...Nozzle, 6...Tank, 7...First chamber, 8...
... Second chamber, 9 ... Water absorption nozzle, 10 ... Upper opening, 11 ... Water injection nozzle, 12 ... Top surface, 13 ...
... recess, 14 ... slit, 15 ... spacer,
16...Slit.

Claims (1)

[Claims for Utility Model Registration] (1) In a liquid dispensing device having one chamber communicating with a water injection pump and a plurality of water injection nozzles communicating with this chamber and vertically installed below the chamber, above the water injection nozzle. A liquid dispensing device characterized in that the periphery of the top surface of the chamber, which is an extension of the above, is a recess that widens downward, and the upper opening of the water injection nozzle is located within this recess. (2) The liquid dispensing device according to claim 1, wherein the recesses are continuous in a sawtooth shape. (3) The liquid dispensing device according to claim 1, wherein the opening of the water injection nozzle is a slit.