JPH0127098Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dispenser for dispensing liquid to multiple locations.

For example, in automatic chemical analyzers and the like, dispensers are used to dispense liquids such as samples, diluents, cleaning solutions, and the like. Among the various dispensers, one is known that dispenses liquid by sucking in liquid through a cylinder and then discharging the liquid. A dispenser is also known in which the discharge side of one cylinder is divided into a plurality of flow paths using a trifurcated pipe or the like. However, in this dispenser, there is a difference in the resistance of each flow path because the tube is clogged with foreign matter. And for these reasons, the minute focus fluctuates. For example, in an analyzer, it is necessary to thoroughly clean the nozzle used in an analyzer with a cleaning liquid to avoid contamination, but if the amount dispensed decreases due to the above-mentioned fluctuations, sufficient cleaning cannot be achieved, which is undesirable.

Also, the discharge side of one pump is divided into multiple flow paths,
There is also known a dispenser in which each valve is provided with a switching valve and the opening and closing of the switching valve is controlled based on time. However, the speed of the piston may vary depending on the voltage or load, and in this case, a disadvantage arises in that the dispensed amount varies.

The present invention was devised to eliminate the above-mentioned drawbacks of the conventional example, and provides a dispenser that detects the position of the driving member that drives the piston and switches the switching valve based on the signal. It is.

The content of the dispenser of the present invention will be explained in detail below based on the illustrated embodiment. In Fig. 1, 1 is the dispenser main body, 2 is a plurality of cylinders installed in the main body 1, 3 is a piston, 4 is a piston flange, 5 is an arm, 6 and 7 are rollers provided on the arm 5, and 8 is an eccentric The cam, 9 is a motor that rotates the eccentric cam, and 10 is a set screw.

In the apparatus shown in FIG. 1, when the motor 9 is driven to rotate the eccentric cam 8, the cam 8 pushes the roller 7 and causes the arm 5 to descend. In this way, while the arm 5 is lowered to the chain line position, the arm 5 pushes down the piston flange 4 and pulls down the piston 3. When the eccentric cam further rotates, it pushes up the roller 6 and the arm 5 rises, pushing up the piston flange 4 and returning to its original state. Here, the distance l ₁ between the upper end 5a and the lower end 5b of the arm 5, and the distance between the piston flange 4 and the upper end 5a of the arm 5.
Let l ₂ be the length of the piston flange ₄ , and the amount of movement of the arm 5 be l _4. When the cam 8 rotates 180° and the arm 5 moves by l ₄ , the piston will move l _4.
-l Move by ₂ . Due to this movement, liquid is sucked into the cylinder 2 from the port 2a. Subsequently, when the cam 8 further rotates by 180 degrees (or reverses by 180 degrees), the arm 5 pushes up the piston flange 4 and returns to its original position.
As a result, the liquid in the syringe 2 is discharged. Further, a photo switch or a limit switch is provided to detect the top dead center and bottom dead center of the arm 5, and the switching valves for the suction side and the discharge side are opened and closed in response to the signals from the photo switch or limit switch. Furthermore, a detector is provided midway through the stroke of the piston to perform valve switching, which will be described later. The thickness of the piston flange
The stroke of the _piston (l ₄
−l ₂ ) can be changed. Therefore, by using an arm extending perpendicular to the drawing and arranging a number of cylinders thereon, it is also possible to operate a number of pistons with one motor. By changing the thickness of the piston flange of each cylinder, the stroke of each cylinder can be changed.

FIG. 2 is a diagram showing an example of operation using a dispenser equipped with a drive mechanism as shown in FIG.
Send the liquid through 6. At this time, when the piston 11 descends, the valve 13 is opened, and when the piston 11 ascends, the valve 15 is first opened to allow liquid to flow through the channel 14, thereby cleaning the probe 18 with, for example, a cleaning liquid. Furthermore, the valve 15 and valve 17 are switched at a predetermined position during the upward stroke of the piston 11 to open the flow path 1.
The probe 19 is washed by flowing a washing liquid through the probe 6 . The switching timing of the valves 15 and 17 is determined, for example, by detecting the position of the arm 5 of the mechanism shown in FIG. 1 with a detector such as a photocoupling or a limit switch, and based on a signal thereof.

Figure 3 is for cleaning one probe 20 from both sides, and the basic configuration and operation are shown in Figure 2.
It is the same as the one shown in the figure. In this case, the same control as in the previous example may be used, that is, valves 15 and 17 may be switched once during the stroke of the piston, or valve 15 and 17 may be switched in a short period of time.
5 and 17 may be switched to alternately switch the supply of liquid from the flow path 14 and the flow path 16 at a fast cycle. In this case, liquid (cleaning liquid) is sprayed alternately from both sides of the probe 20, but in reality, at the moment the valve is closed, some liquid is still coming out from the spray port. Therefore, the cleaning liquid appears to be sprayed almost simultaneously.

FIG. 4 is a diagram showing an example of means for detecting the position of the piston drive member for valve switching. In this figure, the arm 5, rollers 6, 7, cam 8, and motor 9 are the same as those shown in FIG. 21 is a notch portion 21 fixed to the rotating shaft 9a of the motor 9.
22, 23, and 24 are detection switches in which a light emitting element and a light receiving element are arranged facing each other; 22 is for detecting the top dead center position; 23 is for detecting the top dead center position;
24 is for detecting the valve switching position, and 24 is for detecting the bottom dead center. When this detection means is used, when the arm is at the top dead center position, the notch 21a of the light shielding plate 21 is at the detection switch 22 position, and the valve 13 is opened by the signal from the switch 22. Subsequently, when the notch 21a reaches the position of the switch 24, the signal causes the valve 13 to close and the valve 15 to open, allowing the liquid to flow through the flow path 14. Furthermore, when the notch 21a comes to the position of the switch 23, the signal causes the valve 1 to close.
5 is switched to valve 17, and the liquid flows through channel 16.
In this way, the operations described in FIG. 2 or 3 are performed. In order to quickly and alternately switch the valves as described in the explanation of FIG. 3, a large number of detectors may be arranged and the valves may be switched each time a signal from each detector is output. Also, instead of using a large number of detectors, a large number of notches may be provided in the light shielding plate. In that case, the notch may come to the detector 22 while the alternating valve switching operation is being performed, so the detector 22 should be made inoperable except for detecting top dead center, or not provided at all. Top dead center is detected by other detection means.

Although an eccentric cam is used as the drive mechanism in the above explanation, other cams, lead screws, racks and pinions may be used, and an air cylinder may be used instead of a motor. Also, various kinds of detectors other than those shown in FIG. 4 can be considered.

As explained above, the dispenser of the present invention uses dispensers having a plurality of channels alternately, so there is no fluctuation in the dispensed amount and the discharge amount can be accurately regulated.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the drive mechanism of the dispenser of the present invention, Figure 2
Figure 3 shows the configuration of the dispenser of the present invention, and shows an example of cleaning two probes and one probe, respectively, and Figure 4 shows the piston used in the dispenser of the present invention. It is a perspective view showing an example of a position detection mechanism. 2...Cylinder, 3...Piston, 4...Piston flange, 5...Arm, 8...Eccentric cam, 9...Motor.

Claims (1)

[Scope of utility model registration request] A syringe for suctioning and discharging cleaning liquid from a liquid tank, a member for driving a piston of the syringe, a cleaning liquid flow path divided into at least two parts communicating with the discharge side of the syringe, and a cleaning liquid flow path provided in each flow path. The probe is equipped with a switching valve and a detection means for detecting the moving position of the member that drives the piston, and the opening and closing of the switching valve is controlled based on a signal from the detection means to clean the probe. Injector.