JPH0127097Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a device for transferring a liquid such as a reagent in a predetermined amount in an automatic analyzer such as an automatic blood analyzer. The present invention also relates to a liquid transfer device that operates reliably without causing sticking or quantitative errors.

[Prior Art] Conventionally, in automatic analyzers such as automatic blood analyzers, in order to send out a predetermined amount of reagent at regular intervals, a cam fixed to a motor shaft reciprocates a piston in a syringe barrel. Aspirate the liquid into the syringe.
A method of evacuation is generally used. However, this type of conventional method has the disadvantage that the syringe barrel may become stuck. In this case, sticking can be resolved by making the diameter of the piston smaller than the inner diameter of the outer cylinder of the syringe barrel and reducing the contact area through packing, etc. However, on the other hand, it can cause leakage and lead to quantitative errors. This method cannot be said to be preferable because it has the disadvantage of causing a problem.

[Problems to be solved by the invention] Various devices using diaphragms have been proposed in the past in order to solve the above-mentioned drawbacks.
Because the diaphragm deforms or stretches arbitrarily, it is only used when high-accuracy quantitative determination is not required. Because they were always confined at a constant pressure and constantly deformed, the structure became complicated and could not be used in small automatic analyzers.

This invention was created in view of the above points, and includes:
It is an object of the present invention to provide a liquid transfer device that can perform highly accurate quantitative determination by effectively using two diaphragms, and that does not cause sticking, leakage, rust, etc.

[Means for Solving the Problems] In order to achieve the above object, the liquid transfer device of the present invention includes a partition plate that forms an upper space 1 and a lower space 2, as shown in FIGS. 1 to 3. 3, a liquid inlet 4 and a liquid outlet 5 at the upper end of the upper space, and pressure introduction ports 6, 7 at the lower part of the upper space and the upper part of the lower space, respectively; a piston head 10 provided on the piston head; a piston rod 12 connected to the piston head and slidably provided in a center hole 11 bored in a partition plate in the main body; A diaphragm 13 whose portion is fixed to the main body, a sliding disc 14 connected to the lower end of the piston rod and provided so as to be slidable in the lower space, and switching valves 15 and 16 at the pressure introduction ports 6 and 7, respectively. pneumatic supply source 3 connected via
7, 38 and speed control valves 17, 18, a stopper 20 provided at the lower end of the main body, and a guide pin 22 provided through the center of the stopper so as to be always urged upward by a spring 21. , a switch 23 driven by the lower end of the guide pin;
A valve control circuit 24 connected to this switch opens and closes the switching valves 15 and 16.

[Operation] Fig. 1 shows the piston head 10, piston rod 12, and sliding disc 14 reaching the bottom dead center, but in the resting state, as shown in Fig. 3, they always reach the top dead center. It is set so that That is, air pressure from the air pressure supply source 37 is introduced through the pressure introduction port 6, and the diaphragm 13 is connected to the piston head 10.
and the inner wall of the metering chamber 25,
A constant relatively low air pressure is always applied (see Figure 3). In this state,
The pressure inlet 7 is opened to the atmosphere through the speed control valve 18. In order to quantify the liquid from this reset state, the switching valves 15 and 16 are switched simultaneously to open the pressure inlet 6 to the atmosphere via the speed control valve 17, while the pressure inlet 7 is connected to the air pressure supply source 38.
Connect to. That is, the valve control circuit 24 is activated by a quantitative start command from the analyzer, the switching valve 16 is connected to the air pressure supply source 38, and the switching valve 15 is connected to the speed control valve 1.
7 to open to the atmosphere to perform a liquid suction operation. In this case, a force acts to push the sliding disk 14, which is at the top dead center, downward, but the air in the upper space 1 of the main body 8 is gradually exhausted due to the action of the speed control valve 17. , the pressure remains balanced with the pressure in the lower space 2, and the piston rod 12 gradually moves downward while maintaining this pressure state. In other words, since the diaphragm 13 moves to the bottom dead center under constant pressure, the diaphragm 13 comes into close contact with either the periphery of the piston head 10 or the inner wall of the metering chamber 25, forming an inverted sheath-like shape. Causes deformation. As shown in FIG. 1, when the piston rod 12 reaches the bottom dead center regulated by the stopper 20, it no longer moves. When the piston rod 12 reaches the bottom dead center, the guide pin 22 is pushed down to turn on the switch 23, the valve control circuit 24 is activated, the switching valves 15 and 16 are switched again, and the piston rod 12 is moved so that the liquid is sent out. and piston head 1
0 and stop at top dead center while maintaining the pressure from the pneumatic supply source. At this time, the diaphragm 13 maintains a tensioned state, while the liquid inlet 4
is applied with only a pressure equal to atmospheric pressure (a pipe extends to the bottom of the reagent tank and the reagent tank itself is at atmospheric pressure), so that no deformation of the diaphragm 13 occurs. In this case, the relatively low pressure is also advantageous. When the switching valve is switched, the upper space 1 of the main body 8 is opened again.
Pressure is introduced into the lower space 2, and air is gradually discharged to the atmosphere by the speed control valve 18.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. The liquid transfer device of this example has a partition plate 3 that forms an upper space 1 and a lower space 2, a liquid inlet 4 and a liquid outlet 5 at the upper end of the upper space 1, and a lower part of the upper space 1 and a liquid outlet 5. A main body 8 provided with pressure introduction ports 6 and 7 at the upper part of the lower space 2, respectively.
and a piston head 1 provided in the upper space 1.
0, and a main body 8 connected to this piston head 10.
A piston rod 12 is slidably provided in a center hole 11 bored in a partition plate 3 inside, a diaphragm 13 that is in close contact with the lower surface of the piston head 10 and whose peripheral edge is fixed to the main body 8, and the piston rod 12 A sliding disc 14 connected to the lower end of the pressure inlet 6 and slidably provided in the lower space 2;
Pneumatic supply sources 37, 38 and speed control valve 1 connected to each of 7 via switching valves 15, 16
7, 18, and a stopper 20 provided at the bottom end of the main body.
A guide pin 22 is provided in the center of the stopper 20 so as to be constantly urged upward by a spring 21, and a switch 23 is driven by the lower end of the guide pin 22. A valve control circuit 24 connected thereto opens and closes the switching valves 15 and 16. Speed control valve 17, 18
This is constructed by combining a check valve and a throttle valve in parallel to adjust the flow rate of air and control the operating speed of the pneumatic cylinder.

Liquid is introduced into and discharged from an upper space 1 having a liquid inlet 4 and a liquid outlet 5 at its upper end. The piston head 10 has a volume corresponding to the amount of liquid, and repeatedly moves in and out of the upper space 1 to input and discharge liquid. A cylindrical diaphragm 13 that deforms into an inverted sheath shape is held between the base of the piston head 10 and the upper space 1. That is, the peripheral edge of the diaphragm 13 is fixed to the side wall of the main body 8 at approximately the center of the upper space 1 or slightly below the approximately center. The main body having an upper space 1 is
An insertion part 26 having a metering chamber 25 in approximately the upper half of the upper space 1, and a receiving part 2 having a space in approximately the lower half of the upper space 1.
After placing the peripheral edge of the diaphragm 13 on the receiving portion 27 and inserting the flange at the lower end of the insertion portion 26, the ring-shaped fastener 28 is tightened to firmly fix it. 30 and 31 are packing.
On the other hand, the center of the diaphragm 13 is connected to a disk 32 fixed to the piston head 10 and the piston rod.
It is held by The diaphragm 13 is a cylindrical sheet with a bottom lined with cloth, and is made of a molded product such as rubber or synthetic resin.
Teflon (registered trademark of The Dow Chemical Company) is a copolymer of tetrafluoroethylene and hexafluoropropylene that has excellent wear resistance against deformation.
It is preferable to configure the As mentioned above, the main body 8 has an upper space 1 and a lower space 2 sandwiching the central partition plate 3, and pressure introduction ports 6 and 7 to each space are provided. A hole is provided through which the piston rod 12 passes, and the upper and lower parts are kept airtight by packings 33 and 34. Furthermore, at the bottom end of the piston rod 12,
A sliding disk 14 having an O-ring packing 35 on its periphery is fixed. Further, a stopper 2 is provided at the bottom end of the main body 8 at a position where the sliding disc 14 comes into contact.
0 is provided, and an atmosphere opening hole 36 is also provided. The apparatus configured as described above is opened to the atmosphere from the pressure inlets 6, 7 via the switching valves 15, 16, the air pressure supply sources 37, 38, and the speed control valves 17, 18.

Next, the operation of the liquid transfer device of this example configured as described above will be explained in detail. Fig. 1 shows the piston head 10, piston rod 12, and sliding disc 14 reaching the bottom dead center, but the rest state is always when they reach the top dead center, as shown in Fig. 3. It is set to . In other words, air pressure from the air pressure supply source 37 is introduced through the pressure introduction port 6, and the diaphragm 13 is brought into close contact with the outer periphery of the piston head 10 and the inner wall of the metering chamber 25, and the pressure is 0.3Kg/cm ²
A relatively low constant air pressure of ~1 Kg/cm ² is constantly applied (see Figure 3). In this state, the pressure inlet 7 is open to the atmosphere through the speed control valve 18. To measure the liquid from this reset state, switch valve 1
5 and 16 at the same time, the pressure inlet 6 is opened to the atmosphere via the speed control valve 17, while the pressure inlet 7 is connected to the air pressure supply source 38. That is, the valve control circuit 24 is activated in response to a quantitative start command from the analyzer, the switching valve 16 is switched to the air pressure supply source 38, the switching valve 15 is switched to the atmosphere via the speed control valve 17, and a liquid suction operation is performed. . In this case, a force acts to push the sliding disk 14 downward when it is at the top dead center, but due to the action of the speed control valve 17,
Since the air in the upper space 1 of the main body 8 is gradually discharged, the pressure remains balanced with the pressure in the lower space 2, and the piston rod 12 gradually moves downward while maintaining this pressure state. . In other words, since the diaphragm 13 moves to the bottom dead center under constant pressure, the diaphragm 13 comes into close contact with either the periphery of the piston head 10 or the inner wall of the metering chamber 25, forming an inverted sheath-like shape. Causes deformation. As shown in FIG. 1, when the piston rod 12 reaches the bottom dead center regulated by the stopper 20, it no longer moves. When the piston rod 12 reaches the bottom dead center, the guide pin 22 is pushed down to turn on the switch 23, the valve control circuit 24 is activated, the switching valves 15 and 16 are switched again, and the piston rod 12 is moved so that the liquid is sent out. Then, the piston head 10 is raised and stopped at top dead center while maintaining the pressure from the pneumatic supply source.
At this time, the diaphragm 13 maintains a tensioned state,
On the other hand, only a pressure equal to atmospheric pressure is applied to the liquid inlet 4 (a pipe extends to the bottom of the reagent tank, and the reagent tank itself is at atmospheric pressure), so the diaphragm 13 does not deform. . In this case, the relatively low pressure of about 0.3 Kg/cm ² to 1 Kg/cm ² is also advantageous. When the switching valve is switched, pressure is again introduced into the upper space 1 of the main body 8, and air is gradually discharged from the lower space 2 to the atmosphere by the speed control valve 18.

[Effects of the invention] As explained above, the liquid transfer device of the invention has a rest point as the top dead center, and a speed control valve is not provided on the pressure introduction side but on the discharge side (atmospheric release side). Yes, especially because the speed control valve is configured not only to simply control the flow rate of passing air, but also to always apply a constant air pressure to the diaphragm, keeping the diaphragm under tension and always making the same deformation. The space in the metering chamber, which is regulated by the diaphragm and the piston head, does not change even if metering operation is temporarily interrupted, making it possible to minimize metering errors and making it possible to use complex configurations such as duplication. There is no need to do this, and highly accurate quantification can be performed with a simple structure. In addition, since there is no liquid in moving parts such as the piston rod, there is no chance of sticking, rusting, or leaking.Furthermore, a hole is provided in the center of the stopper where the bottom end of the piston rod comes into contact, and a spring is inserted into this hole. The switch is actuated by the guide pin through the guide pin energized by the guide pin, and when the bottom dead center is detected, the switching valve is switched. Even if there are pressure fluctuations,
The suction and discharge operation can be performed reliably, and there are effects such as no quantitative errors occurring.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a cross-sectional explanatory view showing the piston head in a lowered state, Fig. 2 is an enlarged sectional view of the stopper in Fig. 1, and Fig. 3 is an explanatory cross-sectional view showing the piston head in a lowered state. FIG. 1... upper space, 2... lower space, 3... partition plate, 4... liquid inlet, 5... liquid outlet, 6,
7...Pressure inlet, 8...Main body, 10...Piston head, 11...Center hole, 12...Piston rod, 13...Diaphragm, 14...Sliding disc, 15, 16...Switching valve, 17, 18...speed control valve, 20...stopper, 21...spring, 22
... Guide pin, 23 ... Switch, 24 ... Valve control circuit, 25 ... Metering chamber, 26 ... Insertion section, 2
7... Receiving part, 28... Ring-shaped fastener, 30,3
1... Packing, 32... Disc, 33, 34,
35... Packing, 36... Atmospheric release hole, 3
7,38...Air pressure supply source.

Claims (1)

[Scope of utility model registration request] It has a partition plate 3 that forms an upper space 1 and a lower space 2, a liquid inlet 4 and a liquid outlet 5 at the upper end of the upper space, and a pressure introduction port 6 at the lower part of the upper space and the upper part of the lower space, respectively. . 12, a diaphragm 13 that is in close contact with the lower surface of the piston head and whose peripheral edge is fixed to the main body, a sliding disc 14 that is connected to the lower end of the piston rod and is provided so as to be able to slide within the lower space; Pneumatic supply sources 37, 38 and speed control valves 17, 18 connected to the ports 6, 7 via switching valves 15, 16, respectively.
, a stopper 20 provided at the lower end of the main body, and a guide pin 22 provided through the center of the stopper so as to be always urged upward by a spring 21.
A liquid transfer device comprising: a switch 23 driven by the lower end of the guide pin; and a valve control circuit 24 connected to the switch to open and close the switching valves 15 and 16.