JPH03134274A - Valve unit structure for micropump - Google Patents

Abstract

PURPOSE:To obtain a generalized valve structure of a micropump easily built with inferiority by leakage and a cost up suppressed by combining parts, provided with a portion in which at least one valve and flow path are formed, to form a integral part. CONSTITUTION:A valve unit comprises a check valve 101, D unit 104 having a flow path hole 102 and a check valve guide dowel 103 and an E unit 106 for fixedly retaining the check valve 101, and by setting the check valve 101 to the check valve guide dowel 103, the flow path hole 102 is covered. After this setting, by mounting the E unit 106 to the D unit 104 by ultrasonic welding, the valve unit is built. In an F unit 410, the valve unit is set to an inflow port side valve unit in-part 409a while reversely to a delivery port side valve unit in-part 409b, thereafter a metal vibrating plate 412, to which a piezoelectric element 411 is pasted, is similarly pasted to an organic system vibrating plate 413, and by similarly welding to the F unit 410, a micropump is built.

Description

[Detailed description of the invention] [Industrial application field] This article relates to the structure of the valve part of a micropump.

[Prior Art] As shown in FIG. 3, a conventional micro pump includes a piezoelectric element 301, check valves 302a and 302b, an A body 305 having an inlet 303, an outlet 304, and a valve chamber 311, and a pressurizing chamber 306.・Flow passage holes 307a and 307b connecting the pressurization chamber and the valve chamber
308, a metal diaphragm 309, and an organic diaphragm 310.
02 was guided by the valve guide protrusions 312a and 312b of the A body 305, and then fixed by ultrasonic welding of the eight bodies 308 to the A body. In addition,
The metal diaphragm 309 to which the piezoelectric element 301 was attached was attached to an organic diaphragm 310, and this organic diaphragm was also attached and assembled to body B by ultrasonic welding.

[Problem to be solved by the invention]

However, in the conventional structure, the check valve 302 is set on the A body 305 on the inlet side and the outlet side at the same time, and the eight bodies 308 are ultrasonically welded from above, so the ultrasonic energy is applied to the check valve. In addition, a rotating check valve is also generated, and the check valve 302a,
302b, inlet 303 and flow path 307b of eight bodies 308
This caused fluid to leak. Also, the cause of leakage is that the welding is not uniform, and even if the check valve does not rotate, it may also be caused by not being able to securely fix it. If one of the check valves becomes defective due to such a defect, it becomes unusable even if the other valve and the A and B bodies are good.
This led to an increase in costs.

Therefore, the object of the present invention is to provide a valve structure for a micropump that is easy to assemble and has general versatility while suppressing defects and cost increases due to leakage.

[Means for Solving the Problems 1] In the present invention, the problem is solved by combining parts including at least one reverse valve and a part forming a flow path into an integrated part (valve unit).

[Example] Next, details of the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of a valve unit according to the present invention. The structure consists of a check valve 101, an 0 body 104 having a flow passage hole 102 and a check valve guide dowel 103, and an E body 106 (also equipped with a flow passage hole 105) for holding and fixing the reverse valve. ), and the assembly method consists of 0 pieces 104 of the check valve 101.
By setting the check valve guide dowel 103 in the check valve 1
01 covers the channel hole 102. After setting, the valve unit is assembled by attaching the E body 106 to the D body using ultrasonic waves.

FIG. 2 is a plan view of FIG. 1.

The check valve 101 is cap-shaped, and the check valve guide dowel 103 and the corresponding hole in the check valve 101 are track-shaped so that the check valve does not rotate during welding. .

FIG. 4 is a sectional view of a micropump constructed using the valve unit of the present invention on the inlet side and the outlet side.

The structure and assembly are such that the lower body 410 has an inlet 407, a discharge outlet 408, an inlet side valve unit inlet 409a, and a discharge side valve unit inlet 409b, and the valve unit is set in the inlet side valve unit inlet 409a. (The zero-body flow path hole 102a of the valve unit (see Figure 1) and the inflow port 407 of the lower body are aligned.) Also, set the valve unit in the discharge port side valve unit inlet 409b in the opposite direction from the inflow side. The E body flow path hole 105b and the discharge port 408 of the body are combined), and then welded together,
Attach to one body. Thereafter, the metal diaphragm 412 to which the piezoelectric element 411 is attached is similarly attached to the organic diaphragm 413 and then welded to the F body in the same manner, thereby assembling the micropump. Here, a pressurizing chamber 414 is formed in the gap between the valve unit attached to the lower body and the diaphragm 413.

FIGS. 5 and 6 are diagrams showing the operating principle of a micropump using the valve unit of the present invention.

As shown in FIG. 5, when a voltage is applied to the piezoelectric element 411, the metal diaphragm 412 and the organic diaphragm 413 to which the piezoelectric element 411 is attached are deformed in the direction of the arrow. Therefore, the fluid in the pressurizing chamber 414 is pressurized, and the check valve 101a of the inlet side valve unit is pushed downward, pressing down on the flow path hole 102a, thereby stopping the flow of fluid toward the inlet side. Also, the check valve 101b of the discharge port side valve unit is pushed downward to open the flow path hole 102b, and the fluid passes through the flow path hole 102b and the flow path hole 105b and is pushed out to the discharge port 408. Next, as shown in FIG. 6, when a reverse voltage is applied to the piezoelectric element 411, the metal diaphragm 412 and the organic diaphragm 413 are deformed in the direction of the arrow. Therefore, the inside of the pressurizing chamber 414 becomes negative pressure, and the check valve 10 of the discharge side valve unit
1b is sucked upward and blocks the channel hole 102b.

In addition, the check valve 101a of the inflow side valve unit is also sucked upward, opening the channel hole 102a, and the fluid passes through the inlet port 407 and the channel hole 102a, and enters the channel hole 1.
It flows into the pressurizing chamber 414 via 05a.

By repeating the above operations, fluid is continuously sent out from the inlet 407 to the outlet 0408.

FIG. 7 is a cross-sectional view showing another type of valve unit of the present invention, which is a valve unit having a structure in which a valve 701 presses down two locations on the lower flow path 02a and 702b. FIG. 8 is a plan view thereof. FIG. 9 shows a micropump constructed by using this valve unit on the discharge port side of FIG. 4. In this way, different types of micropumps can be manufactured by replacing the valve unit.

In addition, a structure using current micromachining technology, such as a valve made of ceramic and formed by etching or the like, is also conceivable.

It is shown in Figure 1O. In this figure, 1001 is a ceramic valve molded by micromachining. Additionally, a stand 1003 having a flow path 1002 is attached to this valve to form a valve unit. The movement of the valve is similar to that described above, with the portion 1001a moving up and down, and the flow path 100
By opening and closing 2, it makes one movement as a valve. The plan view is as shown in FIG.

FIG. 12 is a sectional view of a micropump constructed using this valve unit. Valves created by micromachining can be made ultra-small, making it possible to control minute flow rates on the order of sub-microliters. In addition to this, various valves and valve units are conceivable, such as those in which the valve portion is molded from plastic.

FIG. 13 is an embodiment of a circuit block diagram of the present invention.

1301 is a power source such as a lithium battery, 1302 is a booster circuit, 1303 is a CPU, 13o4 is a level shifter that converts a low voltage signal into a high voltage signal, and 1305 is a driver that drives the piezoelectric cable 13o6. 13o7 is a display device that displays the flow rate of the pump, and 1308 is a switch that selects the flow rate and the like. The flow rate is selected by the switch 1308, and the CPU 1303 outputs a pump drive signal. CPU signals are generally operated at a voltage of 3 to 5 volts, and piezoelectric elements are operated at a high voltage such as 50 volts. Therefore, the voltage of 3 volts is boosted to 50 volts using the booster circuit 1302, and the level shifter 1
304 converts the signal from the CPU into a 50 volt signal.

FIG. 14(a) shows an embodiment of a directional chopper type booster circuit. 1401.1402 are input terminals, 1403.
1404 is an output terminal. Terminals 1401 and 1403 serve as a common electrode Vdd. 1402 is a low voltage Vssl such as 13 volts, and 1404 is a high voltage Vssh such as 150 volts. 1405 is a boost coil; 14o6 is a first switching element; 1407 is a control circuit that controls on/off of the first switching element 1406;
A feedback circuit 408 is composed of resistors 1409 and 1410. 1411 is a smoothing capacitor for smoothing the output, 1
415 is a reverse current prevention diode, 1412 is a DC input, 1
413 is DC output.

1414 is a control signal that controls the switching element 1406. Switching element 1 by control signal 1414
406 is turned on, the current supplied from the DC power source 1412 flows through the boost coil 14o5 and the switching element 1406.
Energy begins to flow through the booster coil 14o, increases over time, and is proportional to the square of the flowing current value.
When the sixth switching element 1406 stored in the fifth switching element turns off, the energy stored in the boost coil 1405 is stored in the smoothing capacitor 1411 through the backflow prevention diode 1415. Here, backflow prevention diode 1
415, when the switching element 1406 is turned on,
The charges accumulated in smoothing capacitor 1411 are prevented from escaping through switching element 1406. The DC output 1413 is voltage-divided by a feedback circuit 1408 constituted by resistors 14o9.14]0-7' and then sent to a control circuit 14o7.
and its value is compared with a reference voltage inside the control circuit 1407. The control circuit 14o7 switches the control signal 1414 based on the comparison result to control on/off of the switching element 1406 so that the DC output 1413 becomes a constant value.

FIG. 14(b) is an example of a level shifter circuit. 14
21 is a signal input Vin, into which signals of Vdd and Vssl levels are input, and 1422 is a signal output VO, which is input with Vdd and Vssl level signals.
d, a Vssh level signal is output. 1423 is an inverter, 1422 is Vdd, 1425 is Vssh,
1426.1427 is P channel FET, 1428
．． 1429 is an N-channel FET. When a Vdd level signal is input to 1421, transistor 1
427.1428 turns on, transistor 1426.1
429 is turned off. Therefore, Vdd is output to the output 1422. Also, when a Vssl level signal is applied to Vin1421, transistor 1426.142
9 is turned on, transistors 1427 and 1428 are turned off, and a signal at the Vssh level is outputted to the output 1422.

FIG. 14(C) is an example of a driver circuit.

1440 is the input signal Vin, 1441 is the inverter, 1
442.1443 is level sick, 1444.1446
is a P-channel transistor, 1445.1447 is an N-channel transistor, 1449 is a piezoelectric element, and 1450.1451 is an electrode of the piezoelectric element 1449. When a Vdd level signal is applied to the electrode 1440, the transistors 1444 and 1447 are turned off and the transistors 1445 and 1446 are turned on, so that the electrode 145
0 is applied with a voltage of Vssh, and the electrode 1451 is applied with a voltage of Vdd. Further, when a Vssl signal is applied to the electrode 1440, Vdd is applied to the electrode 1450, and the M pole 1451
A voltage of Vssh is applied to drive the piezoelectric element.

[Effects of the invention] By using the structure of the valve unit as described above, the problem of leakage caused by ultrasonic energy at the time of ultrasonic welding, which has been a problem for a long time, can be avoided even if one valve is good but both are defective. This has never happened before, and valve installation has also resulted in defective parts. However, before assembly, we can test the reliability of the valve unit alone to check for leaks, remove defective parts, and ensure that only good parts are installed in the pump. Not only has the defect rate been reduced, but by separating the valves into valve units, which were previously difficult to assemble, a single defect will not affect the overall defect, and the number of man-hours will increase by one level. Despite the fact that it is easier to assemble, the overall effect is that reliability and safety have been greatly improved, and assembly costs have been significantly reduced.

Furthermore, when the valve units are installed on the inflow side and the discharge side, the valve units can be reversed and set by throwing them, which also improves the ease of assembly.

In addition, separate valve units can be used for the inflow side and the discharge side, so you can simply replace the valve unit depending on the purpose (for micromachined ceramic valves for minute flow control). It is now possible to use a valve unit that has already been used, or to use a valve unit that can tolerate some degree of backflow, or to use a valve unit that uses plastic valves, which will suit the purpose of use. By being able to supply the most suitable valve unit, there is no need for excessive quality or insufficient quality.Also, there is a great cost advantage as parts other than the valve unit can be used in common.

Previously, the entire pump was designed according to the type of valve, but now that the valve body has been made into a unit, it is now only necessary to design the valve unit.
There is no need to consider the whole thing, which not only simplifies the process, but also greatly reduces design costs, which has a great effect.

Also, when improving the valves currently in use,
Since it is a valve unit, until the valve can be improved,
For manufacturers, the advantage of using the current product and being able to smoothly switch over to the current product is that by simply replacing the valve unit, all other parts can be used in common.
Not only does it have a huge cost advantage, but it also has the benefit of allowing users to switch from current products without confusion, which in turn increases the confidence of the manufacturer. It's huge.

[Brief explanation of the drawing]

Fig. 1...A sectional view showing the structure of the present invention, Fig. 2...
... Plan view showing the configuration of the present invention, FIG. 3... Cross-sectional view showing a conventional example, FIG. 4... Cross-sectional view of a micropump constructed using the valve unit of the present invention. , Fig. 5, Fig. 6... A sectional view showing the operating principle of a micropump constructed using the valve unit of the present invention, Fig. 7... Showing another example of the valve unit of the present invention. sectional view, Fig. 8... Plan view of Fig. 7, Fig. 9... sectional view of a micropump constructed using the valve unit shown in Fig. 7, Fig. 10... A sectional view showing another example of the valve unit of the present invention, FIG. 11...A plan view of FIG. 1O, FIG. 12...A sectional view of a micropump constructed using the valve unit shown in FIG. 1O. , FIG. 13: A diagram showing an embodiment of a circuit block diagram of the present invention. FIG. 14(a): A diagram showing an embodiment of a chopper type booster circuit. FIG. 14(b): A diagram showing an example of a level thick circuit. FIG. 14(C)... A diagram showing an example of a driver circuit. that's all

Claims (1)

[Claims] 1) A diaphragm made of an organic or ceramic piezoelectric element, a valve that opens and closes a flow path through which liquid or gas passes, an inlet, an outlet, a pressurizing chamber that pressurizes the liquid, etc. A valve unit structure for a micropump, characterized in that a micropump structure for pushing out fluid by means of a micropump is made into an integrated part by combining parts including at least one of the valves and a part forming a flow path. 2) The valve unit structure of a micropump according to claim 1, wherein the valve unit is used in common on the inlet side and the outlet side. 3) A valve unit structure for a micropump according to claim 1, wherein different valve units are used on the inlet side and the outlet side, respectively.