CN1051073A - microelectrochemical pump - Google Patents

Abstract

Disclosed in this specification is a continuous Or a portable microelectrochemical pump that pumps liquid intermittently at a tiny rate. The electrochemical pump is made of: made of ceramic or organic material, fed to the control electric a piezoelectric element that deforms when pressed; and adhering the piezoelectric element to on, and deforms in unison with the deformation of the piezoelectric element composed of vibrating diaphragms. With the expansion and contraction of the vibrating diaphragm, the micro electrochemical pump becomes Shape or suck liquid from the suction port, or discharge the liquid sucked from the suction port shot out of its radiation port.

Description

The present invention relates to a portable type micro-radiation device for continuously or intermittently discharging liquid at a minute rate for a predetermined period of time.

In the prior art, such a microradiation device has been disclosed, for example, in Japanese Laid-Open Patent Publication No. 54(1979)-12191 and Japanese Patent Publication No. 61(1986)-22599. In the disclosed microradiation device, an electromagnetic actuator is used as the prime mover and is coupled to a transmission mechanism having a variable size gear combination so that a syringe can be directly pushed by an arm.

However, since this device uses an electromagnetic actuator, it is weak against electromagnetic noise and consumes a large amount of current. Moreover, because the gear transmission mechanism is used, due to backlash movement, the radiation amount difference of the device is increased and the structure is complicated. In addition, the need to push the syringe also increases the overall size, thereby limiting portability.

An object of the present invention is to provide a microelectrochemical pump, that is, a small portable micro-radiation device that is highly resistant to electromagnetic noise, has such a small current consumption that it can be carried with a small battery, and has good radiation accuracy.

Another object of the present invention is to provide a small microelectrochemical pump that is easy to assemble and has versatility while suppressing failures due to leaks and increase in product cost.

According to one aspect of the present invention, there is provided a micro-electrochemical pump with a pump assembly, the pump assembly includes: a piezoelectric element made of ceramic or organic material that deforms when a control voltage is applied; A vibrating diaphragm to which an element is adhered and which deforms in unison with the deformation of said piezoelectric element; according to the deformation of said vibrating diaphragm in a predetermined direction, its suction port releases its closed state, sucking from the suction port liquid inlet pipe check valve; and according to the deformation of the vibrating diaphragm in the above-mentioned opposite direction, the discharge hole is released from its closed state, and the liquid sucked from the suction port is radiated from the discharge port through the discharge hole. Liquid check valve.

If a control voltage is applied to the piezoelectric element, the piezoelectric element expands and contracts in the radial direction. With these expansion and contraction movements, the vibrating diaphragm attached to the piezoelectric element vibrates up and down, thereby sucking the liquid in the container into the pump unit and discharging it from the discharge port.

Since a pump using a piezoelectric element is used as a microelectrochemical pump, it can be configured with a smaller number of parts than a radiation device using an electromagnetic actuator, thereby enabling miniaturization and reduction in product cost. In addition, since the shape of the container is not limited, the shape of the radiation device can have more degrees of freedom, and since the piezoelectric element is a voltage-driven actuator, its current consumption is as small as the order of μA . Therefore, even if a lithium battery is used, a portable microelectrochemical pump with a long service life can be obtained.

On the other hand, microelectrochemical pumps employing electromagnetic actuators cannot adjust the flow rate step by step. However, in the present invention, a piezoelectric element is used so that the displacement, that is, the amount of radiation can be controlled according to the voltage. As a result, the amount of radiation can be controlled according to the frequency, and the flow rate can be controlled according to the voltage of each stage, so that the amount of radiation can be finely adjusted. Moreover, the displacement of the piezoelectric element can be controlled to less than 1 µm without possible backlash caused by the gear transmission mechanism as in the radiation device with the electromagnetic actuator. For example, if a pressurized chamber diameter of 10 mm is used, the displacement control can be accurate to a very small amount of 0.02 microliters. Moreover, since the piezoelectric element is not affected by the magnetic field, even in a magnetic field environment, it will not cause malfunction like the electromagnetic actuator, so good safety can be obtained.

Furthermore, according to another aspect of the invention, the pump assembly of the microelectrochemical pump has a monolithic (valve) component, wherein the monolithic component combines at least one non-return valve with a component forming a channel portion. With such a valve member, it is possible to solve the existing problem of leakage caused by ultrasonic energy at the time of ultrasonic welding. In the prior art, failure of even one valve would cause failure of both valves and valve accessories. However, according to this aspect of the invention, the valve member itself can be tested for reliability such as leakage before assembly. As a result, defective components, if present, can be excluded, and only good components can be reliably loaded into the pump. This reduces the reject rate. In addition, the previously difficult-to-assemble valve is divided into valve components so that defects in one component do not propagate to the whole. This makes the valve easy to assemble, although an additional step is required. On the whole, the reliability and safety are greatly improved, and the product cost can be significantly reduced. Thus, the present invention can provide significant practical effects.

On the other hand, if the valve members are to be installed in the suction side and the discharge side, they can be placed arbitrarily regardless of which side they are set on.

Furthermore, since different valve members can be used on the suction side and the discharge side, they can be interchanged accordingly. For a fine flow control, a valve member constructed from a micromachined ceramic valve can be used. The valve member may consist of a plastic valve, provided a small reverse flow is permitted or if low production costs are desired. Thus, it is possible to provide an optimum valve member in consideration of the purpose of use. This rules out over- or under-quality. Additionally, components other than the valve member can often be used to provide cost advantages.

In prior art designs, the entire pump is designed according to its type. However, in the present invention, since the valve member is integrated, it is sufficient to design only the valve member instead of the whole body. Therefore, the design work is simplified to significantly reduce the cost.

On the other hand, if an existing valve is to be improved, the valve member can be continuously used because of the valve member until it is improved. Other parts can usually be used by replacing the valve member at the end of the retrofit. The advantage of this smooth replacement of existing devices is not only significant cost savings in terms of processing, but also the replacement of existing valves without disruption on the part of the user. Furthermore, this advantage increases the trust in the maker with a remarkable advantage.

According to another aspect of the present invention, the micro-electrochemical pump is formed by bonding multiple ceramic or organic piezoelectric elements on the vibrating diaphragm.

In this way it is possible to provide a pump assembly with high flow in one stage which is hardly affected by back pressure. On the other hand, the existing bimorph vibrating diaphragm has piezoelectric elements on both sides of it, and it cannot be used in in corrosive or conductive environments. However, since the piezoelectric element of the present invention is adhered to one face of the vibrating diaphragm, it is not in close contact with the liquid in the pressurized chamber. Thus, even if the pressurized chamber is in a corrosive or conductive environment, the pump assembly can still be constructed so that it will not be short-circuited or subject to contact corrosion, thereby increasing the reliability and service life of the pump assembly.

According to still another aspect of the present invention, in the pump assembly of the microelectrochemical pump, the suction valve cavity and the discharge valve cavity are closed by the vibrating diaphragm in plane contact with the central plate member. As a result, backflow can be ruled out although there is more or less leakage. Furthermore, by restricting the displacement of the vibrating diaphragm with the plate member, it is possible to construct a microelectrochemical pump having a low dependence on back pressure. On the other hand, where defoaming is to be done from the pump assembly, it may be helpful for higher flow rates to defoam if it is performed under vacuum or pressurization. Foaming is easily eliminated by creating a space of a specific size formed by the deformation of the vibrating diaphragm to accelerate the flow rate.

According to still another aspect of the present invention, in addition, the liquid can be injected from the outside into the pump and container which have been vacuumed and sealed. In the case where the liquid medicine is directly injected into the human body for medical purposes, it is possible to completely prevent gas from infiltrating into the liquid medicine to ensure a remarkably high safety.

In addition, if liquid medicine or alcohol is to be used as the emanating fluid, the pump components used must be made of highly chemical-resistant materials such as polypropylene. In this case, the electrode metal plate and the polypropylene plate cannot be adhered with an adhesive. Therefore, in the present invention, the electrode metal plates having the tapered holes are insert-molded so that they are integrated with the vibrating diaphragm. Thus, it is possible to obtain a reusable pump unit that does not peel off, has good durability, and provides high reliability as a whole. Furthermore, if the diaphragm is constructed with the solvent-welded protrusion, it can be easily welded to the main body without any gasket to ensure waterproofness with the main body. Thus, a well-fitted pump assembly can be produced at low cost.

According to still another aspect of the present invention, the first valve member for closing the suction port and the second valve member for closing the discharge hole are pushed by separate compression springs, and the elastic force of each spring can be freely set. This makes it possible to freely set the valve opening pressure. Therefore, if the pump is used in a situation where there are many external vibrations, the compression spring can be set to have an elastic force to overcome the vibrations, so that the pump can obtain a safer valve structure. Moreover, if the valve structure of the present invention is used, the energy level of anti-backflow can be significantly improved due to good contact and sealing characteristics without increasing the flow rate of backflow, thereby improving the reliability to a higher level.

The above and other objects, advantages and features of the present invention will become more apparent through the following description with reference to the accompanying drawings.

Fig. 1 and 2 are respectively the sectional view and the top plan view showing the microelectrochemical pump according to an embodiment of the present invention,

Fig. 3 is a sectional view showing an example of the structure of the pump assembly of Fig. 1,

Fig. 4 is a circuit block diagram showing a microelectrochemical pump according to an embodiment of the present invention,

Fig. 5 is a circuit diagram showing an embodiment of a booster circuit,

Figure 6 is a circuit diagram showing an implementation of a level shifter,

Fig. 7 is a circuit diagram showing an example of a driver,

8(a) and 8(b) are cross-sectional views illustrating the operation of the pump assembly of FIG. 3,

Fig. 9 is a time chart showing the driving signals of the pump assembly,

Figures 10 and 11 are cross-sectional and top plan views, respectively, showing an embodiment of a valve member,

Fig. 12 is a sectional view showing a microelectrochemical pump constituted by the valve member of Fig. 10,

13(a) and 13(b) are cross-sectional views illustrating the operation of the microelectrochemical pump of FIG. 12,

Figures 14 and 15 are respectively sectional and top plan views showing another embodiment of the valve member,

Fig. 16 is a sectional view showing a microelectrochemical pump constituted by the valve member of Fig. 14,

Figures 17 and 18 are respectively sectional and top plan views showing another embodiment of the valve member,

Fig. 19 is a sectional view showing a microelectrochemical pump constituted by the valve member of Fig. 17,

Fig. 20 is a sectional view showing another embodiment of the pump assembly structure,

Fig. 21 is a characteristic graph illustrating the relationship between back pressure and flow rate in the case of using a bimorph piezoelectric element and a unimorph piezoelectric element,

Fig. 22 is a sectional view showing another embodiment of the structure of the pump assembly,

Figures 23(a) and 23(b) are sectional views illustrating the action of the pump assembly of Figure 22,

Figure 24 is a characteristic graph illustrating the relationship between flow rate and back pressure for the pump assembly configuration of Figure 22,

Fig. 25 is a sectional view showing another embodiment of the pump assembly structure,

Figures 26 and 27 are a top plan view and a sectional view, respectively, showing the sealing top cover,

Fig. 28 is a sectional view showing a state where a container is connected to the pump assembly,

Figures 29(a) and 29(b) are sectional views illustrating the action of the pump assembly of Figure 25,

Fig. 30 is a sectional view showing another embodiment of the pump assembly structure,

Figures 31 and 32 are top plan and cross-sectional views showing the vibrating diaphragm of Figure 30, respectively,

Figures 33(a) and 33(b) are sectional views illustrating the action of the pump assembly of Figure 30,

Fig. 34 is a sectional view showing another embodiment of the pump assembly structure,

Figures 35(a) and 35(b) are sectional views illustrating the action of the pump assembly of Figure 34,

Fig. 36 is a sectional view showing another embodiment of the pump assembly structure,

37( a ) and 37 ( b ) are sectional views illustrating the operation of the suction side valve and the discharge side valve, respectively,

38(a) and 38(b) are cross-sectional views illustrating the structure and action of another embodiment of the valve structure, respectively,

39(a) and 39(b) are cross-sectional views illustrating the structure and action of another embodiment of the valve structure, respectively,

Figure 40 is a side elevational view showing an embodiment wherein the retainer plate is integrated with the check valve flap,

Fig. 41 is a cross-sectional view showing another embodiment of the pump assembly structure,

42( a ) and 42 ( b ) are sectional views illustrating the operation of the suction side valve and the discharge side valve, respectively,

43(a) and 43(b) are cross-sectional views illustrating the structure and action of the other implementation side of the valve structure, respectively,

Fig. 44 is a sectional view showing another embodiment of the structure of the pump assembly,

45( a ) and 45 ( b ) are sectional views illustrating the operation of the suction side valve and the discharge side valve, respectively,

46(a) and 46(b) are cross-sectional views illustrating the structure and action of another embodiment of the valve structure, respectively,

47(a) and 47(b) are cross-sectional views illustrating the structure and action of another embodiment of the valve structure, respectively,

Figures 48(a) and 48(b) are sectional views illustrating the structure and operation of another embodiment of the valve structure, respectively.

1 and 2 are respectively a sectional view and a top plan view showing a microelectrochemical pump according to an embodiment of the present invention.

The microelectrochemical pump of this embodiment includes: a pump assembly 101 made of piezoelectric elements, a vibrating diaphragm, a check valve and a main body with a suction port, a discharge port and a channel; an integrated assembly for operating the pump assembly 101 circuit 102; circuit block 103 consisting of electrical components and substrates such as said integrated circuit 102, booster coil or capacitor; battery 104 serving as a power source; external control switch 105; container 106; cover 107; and display 108.

FIG. 3 is a cross-sectional view of a detail of the pump assembly 101 . The pump assembly 101 includes: a piezoelectric element 201 , an electrode metal plate 202 , a vibrating diaphragm 203 , a liquid inlet check valve 204 , a liquid discharge check valve 205 , an A body 210 and a B body 214 . The A main body 210 is constituted by a suction port 206, a discharge port 207, a suction valve chamber 208 and a discharge valve chamber 209. The B body forms a pressurized chamber 211 together with the diaphragm 203 and suction ports 212 and discharge ports 213 for providing communication between said pressurized chamber 211 and the valve chambers 208 and 209 . Assemble the B body with ultrasonic solvent welding, or adhere it to the A body 210 with the check valves 204 and 205 set therebetween, and the vibrating membrane 203 with the piezoelectric element 201 and electrode metal adhered thereto plate 202.

FIG. 4 shows an embodiment of the circuit block 103 of FIG. 1 . The circuit block includes: a power supply 301 such as a lithium battery, a boost circuit 302, a CPU 303, a level shifter 304 for converting a low-voltage signal into a high-voltage signal, and a driver 305 for driving a piezoelectric element 306. A display 307 to show the charge of the pump 8 or the like, and a switch 308 to select the flow rate or the like. When the flow rate is selected by the switch 308 , a pump drive signal is output from the CPU 303 . Generally speaking, the signal of the CPU 303 operates at a voltage of 3 to 5V, and the piezoelectric element 306 operates at a high voltage such as 50V. Then, the 3V voltage is boosted, for example, to 50V by the booster circuit 302 , and the signal from the CPU 303 is converted into a 50V signal by the level shifter 304 .

FIG. 5 is a circuit diagram showing an example of a chopper boost circuit exemplifying the boost circuit 302 in FIG. 4 . Reference numerals 401 and 402 denote a pair of input terminals, and reference numerals 403 and 404 denote a pair of output terminals. The input terminal 401 and the output terminal 403 provide a common electrode Vdd. The input terminal 402 feeds a low voltage Vss1 such as -3V, and the output terminal 405 outputs a high voltage Vssh such as -50V. Reference numeral 405 denotes a boosting coil, reference numeral 406 denotes a first switching element, and reference numeral 407 denotes a control circuit for turning on or off the first switching element 406 . Reference numeral 408 denotes a feedback circuit composed of resistors 409 and 410 . Reference numeral 411 denotes a smoothing capacitor for smoothing the output, reference numeral 415 denotes a reverse current blocking diode; reference numeral 412 denotes a DC input; reference numeral 413 denotes a DC output;

If the switching element 406 is turned on by the control signal 414, the current fed from the DC input 412 starts to flow through the boost coil 405 and the switching element 406 and increases with time, so that the voltage corresponding to the voltage stored in the boost coil 405 is The energy that flows is proportional to the square of the current.

Next, if the switching element 406 is turned off, the energy stored in the booster coil 405 is stored in the smoothing capacitor 411 through the reverse current blocking diode 415 . Here, the reverse current blocking diode 415 prevents the charge stored in the smoothing capacitor 411 from being discharged to flow through the switching element 406 when the switching element 406 is turned on.

The voltage of the DC input 413 is divided by the feedback circuit 408 composed of resistors 409 and 410 , and its value is compared with the reference voltage in the control circuit 407 . Based on the comparison result, the control circuit switches the control signal 414 to switch the switching element 406 on or off, thus making the flow output 413 constant.

FIG. 6 is a circuit diagram showing an example of the level shifter 304 in FIG. 3 . Reference numeral 421 in the figure denotes an input signal Vin for feeding signals of Vdd and Vssl levels, and 422 denotes an output signal for outputting signals of Vdd and Vssh levels. Reference numeral 423 denotes an inverter, reference numeral 424 denotes a level Vdd, reference numeral 425 denotes a level Vssh, reference numerals 426 and 427 denote P-channel field effect transistors, and reference numerals 428 and 429 denote N-channel field effect transistors.

If the input signal Vin 421 is input at the level Vdd, the transistors 427 and 428 are turned on, and the transistors 426 and 429 are turned off. As a result, the output signal Vo 422 is converted into a signal of level Vdd. On the other hand, if a signal of Vssl level is input as the input signal Vin421, the transistors 426 and 429 are turned on, and the transistors 427 and 428 are turned off. As a result, the output signal Vo 422 is transformed into a signal whose level is Vssh.

FIG. 7 is a circuit diagram showing an example of the driver circuit 305 in FIG. 3 . Reference numeral 440 denotes an input signal Vin, reference numeral 441 denotes a converter, reference numerals 442 and 443 denote level shifters, reference numerals 444 and 446 denote P-channel transistors, reference numerals 445 and 447 denote N-channel transistors, and reference numerals 450 and 451 denote electrodes of the piezoelectric element 201 . When a signal with a level of Vdd is input as the input signal Vin 440, the transistors 444 and 447 are turned off, and the transistors 445 and 446 are turned on. As a result, a voltage of Vssh level is supplied to the electrode 450 and a voltage of Vdd level is supplied to the electrode 451 . Conversely, when a signal with a level of Vssl is input as the input signal Vin 440, likewise, a voltage with a level of Vdd is supplied to the electrode 450, and a voltage with a level of Vssh is supplied to the electrode 451 to drive the piezoelectric element 201.

8(a) and 8(b) are cross-sectional views illustrating the operation of the pump assembly 101 in FIG. 3 . It is assumed that the pressurized chamber 211 and the valve chambers 208 and 209 are filled with liquid. It is also assumed that if the upper electrode 450 of the piezoelectric element 201 is fed with a voltage Vdd and if the lower electrode 451 thereof is fed with a voltage Vssh, the piezoelectric element 201 contracts radially.

FIG. 9 shows the driving waveforms of the pump assembly 101 . Fig. 9(a) shows the drive waveform output from the CPU 303 of Fig. 4, and Figs. 9(b) and 9(c) show the drive voltage waveforms applied to the electrodes 450 and 451 in Fig. 8, respectively. For a time period 90 in FIG. 9, the electrode 450 is fed with a voltage Vdd and the electrode 451 is fed with a voltage Vssh, so that the piezoelectric element 201 undergoes radial contraction. As a result of this radial contraction, the vibrating diaphragm 202 protrudes downward, as shown in Figure 8(a). As a result, the liquid in the pressurization chamber 211 is pressurized to depress the discharge check valve 205 , thus forcing the liquid to flow to the discharge port 207 . At this time, the liquid is prevented from flowing back from the pressurized chamber 211 to the suction port 206 by means of the liquid inlet check valve 204 .

Next, for the time period 902 of FIG. 9 , the electrode 450 is fed with the voltage Vssh, and the electrode 451 is fed with the voltage Vdd, so that the piezoelectric element 201 expands radially. As a result of this stretching, the vibrating diaphragm 202 protrudes upward, as shown in FIG. 8(b). Then, the liquid in the pressurized chamber 211 is evacuated to push up the liquid inlet check valve, thereby forcing the liquid to flow from the suction port 206 to the pressurized chamber 211 . At this time, liquid is prevented from passing from the pressurized chamber 211 to the discharge port 207 by the action of the liquid discharge check valve 205 .

Therefore, by repeating the actions described so far with reference to FIGS. 8( a ) and 8 ( b ), liquid can be sucked from the suction port 206 to the discharge port 207 .

Fig. 10 is a sectional view showing an embodiment of the valve member of the present invention, and Fig. 11 is a top plan view thereof. The valve member is generally represented by reference numeral 220, and it consists of a check valve 221, a D main body with a passage opening 222 and a check valve guide tenon 223, and a valve for fixing the check valve (also playing the role of passage opening 225). The E-body 226 constitutes. The valve member 220 thus constituted is assembled as follows. First, set the check valve 221 on the guide tenon 223 of the D main body. The non-return valve 221 then covers the passage opening 222 . Thereafter, the E body 226 is ultrasonically welded to the D body 224 to assemble the valve member 220 .

The check valve 221 is processed into a top cover shape, and the corresponding openings of the check valve guide tenon 223 and the check valve 221 are tracked and processed into a shape that can prevent the check valve 221 from rotating during the welding operation.

FIG. 12 is a cross-sectional view showing a microelectrochemical pump constructed using the valve member 220 of FIGS. 10 and 11 on the suction and discharge port sides.

In this micro electrochemical pump, the A main body 250 is processed with a suction port 206, a discharge port 207, a suction side valve member seat 220a, and a discharge side valve member seat 220b. Place the valve member 220 in its suction side receptacle 220a (on which the passage opening 222a of the D body of the valve member as shown in FIG. 10 and the A body suction port 206 are aligned) and place the valve member 220 in Opposite the suction side is the discharge side receptacle 220b (where the passage opening 225b of the E body of the valve member and the discharge port 207 of the A body align). Thereafter, those components are welded to the A main body 250 one by one. Then, the electrode metal plate 202 on which the piezoelectric element 201 is adhered is also adhered to the vibrating diaphragm 203 of organic material, and is also welded to the main body A, thus assembling the micro electrochemical pump. At this time, a pressure control 211 is formed between the valve member and the vibrating diaphragm 203 assembled in the same manner as the A main body. Here, in FIG. 12 , a letter a is suffixed to each part of the suction side valve member 220 , and a letter b is suffixed to each part of the discharge side valve member 220 .

13( a ) and 13 ( b ) are cross-sectional views illustrating the operation of the microelectrochemical pump shown in FIG. 12 .

If a voltage is applied to the piezoelectric element 201, as shown in Fig. 13(a), the metal vibrating diaphragm 202 and the organic material vibrating diaphragm 203 with the piezoelectric element 201 adhered thereto are deformed in the direction of the arrow. As a result, the liquid in the pressurizing chamber 211 is pressurized to depress the check valve 221a of the suction side valve member 220, so that the passage opening 222a is closed to block the flow of the liquid to the suction side. The check valve 221b of the discharge side valve member 220 is also pressurized to open the liquid opening 222b so that liquid is drawn to the discharge port 207 through the discharge valve chamber 209, the passage opening 222b and the passage opening 225b.

Next, if a reverse voltage is applied to the piezoelectric element 201, as shown in Figure 13(b), the electrode metal plate 202 and the organic material diaphragm 203 are deformed in the direction of the arrow, that is, as shown in Figure 13(a) The deformation is carried out in the opposite direction of the situation. As a result, the pressurized chamber 211 is evacuated, so that the check valve 221b of the discharge valve member 220 is sucked up to close the passage opening 222b. Also, the check valve 221a of the suction side valve member 220 is sucked up to open the passage opening 222a, so that the liquid flows into the pressurizing chamber 211 through the suction port 206, the passage opening 222a, the liquid inlet chamber 208 and the passage opening 225a.

Therefore, by repeating the actions described so far with reference to FIGS. 13( a ) and 13 ( b ), liquid can be continuously sucked from the suction port 206 to the discharge port 207 .

FIG. 14 is a cross-sectional view of another embodiment of a valve member 220 structure, and FIG. 15 is a top plan view thereof. The valve member 220 forms two passage openings 234 and 235 which are closed by a valve 231 . A microelectrochemical pump structure using such a valve member on the discharge side of FIG. 12 is demonstrated by the microelectrochemical pump of FIG. 16 . In this way, another type of microelectrochemical pump can be manufactured by replacing the valve member.

Another structure can be envisaged by using and etching a valve made of ceramics by means of existing micromachining techniques. This structure is shown in Figures 17 and 18, in which reference numeral 241 designates a ceramic valve formed by micromachining. In addition, the valve member is constructed by attaching a base having a channel 242 to a ceramic valve 241 . Like the valve member described above, movement of the valve is achieved by means of the vertically moving portion 241a to open or close the passage 242 .

Fig. 19 is a cross-sectional view showing a microelectrochemical pump constructed with the valve member of Figs. 17 and 18 .

This embodiment is equipped with a seat 244 for holding the bottom surface 243 of the discharge side valve in the A body 250 . The base 244 is processed with a channel 245 corresponding to the channel 242 . Also, in this embodiment, the inlet valve chamber 208 doubles as a pressurized chamber.

The micro-machined valve can be miniaturized to realize micro-flow control on the order of sub-microliters. Also, by employing a micromachining technique, the silicon substrate can be etched to integrate the valve, vibrating membrane, and body. Various other valves and valve components are conceivable by partially molding them in plastic.

FIG. 20 is a cross-sectional view showing another embodiment of the pump unit 101 . This embodiment differs from the pump assembly of FIG. 3 in that it is equipped with a second piezoelectric element 215 in addition to the first piezoelectric element 201 . Adhere the two piezoelectric elements with different polarization directions. In addition, an electrode 452 is superimposed on the second piezoelectric element, the electrode is set to a common potential, and driving power is applied to the electrodes 450 and 451 (wherein, for example, the electrode 452 is set to 0V, and 50V is applied to the electrodes 450 and 451).

The actions of the pump assembly of Fig. 20 are basically similar to those of Figs. 8(a) and 8(b), and thus their descriptions are omitted.

FIG. 21 is a characteristic graph showing the relationship between the flow rate and the back pressure of the pump assembly of FIG. 20 . Flow rate versus backpressure is plotted in Figure 21. Curve 801 shows the characteristic curve of the pump assembly (according to the embodiment of FIG. 3 ) with only one piezoelectric element and the unimorph piezoelectric element, while characteristic curve 802 shows the characteristic curve of the pump assembly of FIG. 20 .

In general, the flow rate is lower because the displacement of the diaphragm becomes smaller at higher back pressure. By adopting the bimorph piezoelectric element with two piezoelectric elements, since the thickness of each piezoelectric element of the bimorph is half of the thickness of the piezoelectric element of the unimorph, the displacement is doubled. In addition, since the piezoelectric elements of the two bimorphs are arranged side by side, the displacement is four times larger than that of the unimorph piezoelectric elements when the piezoelectric elements are arranged side by side. As a result, the flow rate becomes higher than in the unimorph case. If the thickness of the bimorph is increased, the vibrating device is less affected by the back pressure due to its increased rigidity.

FIG. 22 is a sectional view showing another embodiment of the structure of the pump unit 101. As shown in FIG. This pump unit has no components corresponding to the pressurized chamber 211 of FIG. 3, and the B main body 214a and the vibrating diaphragm 203 are fixed only at their peripheries.

23(a) and 23(b) are sectional views illustrating the operation of the pump unit. For example, if the voltage Vssh is fed to the electrode 450 and the voltage Vdd is fed to the electrode 451, the piezoelectric element 201 is radially expanded so that it protrudes upward, as shown in FIG. 23(b). Then, the gap between the vibrating diaphragm 203 and the B body 214a is evacuated so that they are separated from each other to form a space 211a. As a result, the liquid in the liquid inlet chamber 208 is evacuated thereby sucking up the liquid inlet check valve 204 . The liquid is thus sucked from the suction port 206 to the aforementioned space 211a. Next, if the voltage Vdd is fed to the electrode 450 and the voltage Vssh is fed to the electrode 451, the piezoelectric element 201 is radially contracted, so that the vibrating diaphragm 203 will conversely protrude downward, but its displacement is limited by the B body 214a, As shown in Fig. 23(a), the space 211a is thereby eliminated. As a result, the liquid in the space 211 a is pressurized to depress the discharge check valve 205 , prompting the liquid to flow to the discharge port 207 . Therefore, by repeating the actions described so far with reference to FIGS. 23( a ) and 23 ( b ), liquid can be sucked from the suction port 206 to the liquid discharge port 207 . In addition, the action of the liquid inlet check valve 204 during liquid discharge and the action of the liquid discharge check valve 205 during liquid intake are similar to those shown in FIGS. 8( a ) and 8 ( b ).

FIG. 24 is a characteristic graph showing the relationship between the flow rate and the back pressure of the pump assembly of FIG. 22 . Flow rate versus backpressure is plotted in Figure 24. Curve 803 represents (in the embodiment of FIG. 3 ) the characteristic curve in the case of a pressurized chamber formed between B body 214 and vibrating diaphragm 203 , while curve 804 represents the characteristic curve of the pump assembly of FIG. 22 . Generally speaking, the flow rate is lower because the displacement of the diaphragm becomes smaller at higher back pressure. However, since the B body 214a acts as a baffle, it is possible to obtain a pump assembly capable of discharging a constant flow rate up to a certain back pressure.

FIG. 25 is a sectional view showing another embodiment of the structure of the pump unit 101. As shown in FIG. This embodiment is equipped with rubber top caps 255 and 256 to seal the suction port 206 and discharge port 207 respectively. Caps 255 and 256 are provided with springs 257 and 258 extending therethrough.

Figures 26 and 27 are top plan and cross-sectional views showing the sealing cap 255 or 256, respectively. Reference numeral 259 denotes a top cover molded from rubber such as silicone resin. A cap 260 having a hole 261, made of metal or plastic, serves to guide the syringe when preparing to inject liquid through it from the outside.

Figure 28 shows another embodiment in which the suction port 206 of the pump assembly is connected to a container 263 through a tube 262, and the container 263 is partially equipped with a rubber top cover 255. Incidentally, reference numeral 264 denotes a plastic ring for holding the rubber top cover 255 in the container 263 .

If the microelectrochemical pump is to be used to inject medicinal liquid directly into the human body for therapeutic purposes, for example, it is necessary to change the pump and the container for purification. Therefore, the pump unit and the inside of the container are previously evacuated and sealed with a sealing rubber top. The liquid can then be injected by inserting the syringe 257 from said side into the pump assembly or container rubber top, thereby filling only the interior of the pump or container with liquid. The liquid can be emitted outside by means of a syringe 258 .

29(a) and 29(b) are sectional views illustrating the operation of the pump assembly of FIG. 25. FIG. If the voltage Vdd is supplied to the electrode 450 and the voltage Vssh is supplied to the electrode 451, the piezoelectric element 201 contracts radially, making the vibrating diaphragm 203 protrude downward, as shown in FIG. 29( a ). As a result, the liquid in the pressurization chamber 211 is pressurized to depress the discharge check valve 205 , thereby forcing the liquid to flow to the discharge port 207 . Next, if the voltage Vssh is fed to the electrode 450 and the voltage Vdd is fed to the electrode 451, the piezoelectric element 201 is radially extended, so that the vibrating diaphragm 203 protrudes downward, as shown in FIG. 29(b). Then, the liquid in the pressurized chamber 211 is evacuated to push the liquid inlet check valve 204 upward, thereby forcing the liquid to flow from the suction port 206 to the pressurized chamber 211 . In this way, the liquid can be sucked from the suction port 206 to the discharge port 207 by repeating the actions described so far with reference to FIGS. 29( a ) and 29 ( b ).

FIG. 30 is a sectional view showing another embodiment of the structure of the pump unit 101. As shown in FIG. In this embodiment, the diaphragm 203 is formed from a flat sheet 274 of plastic.

31 and 32 are a top plan view and a sectional view showing the diaphragm 203, respectively. Since the electrode metal plate 202 is processed with tapered holes 270, the plastic flat diaphragm 274 can be firmly fixed on the electrode metal plate 202 by filling the aforementioned holes with plastic. Reference numeral 271 denotes a positioning plastic ring to be used when preparing to paste the piezoelectric element. Reference numeral 272 denotes a terminal fitting for welding electrodes. Reference numeral 273 denotes a protrusion for ultrasonic welding of the B main body 214 which is fixed so that liquid cannot flow through it.

33(a) and 33(b) are sectional views illustrating the operation of the pump assembly of FIG. 30. FIG.

If the voltage Vdd is fed to the electrode 450 and the voltage Vssh is fed to the electrode 451, the piezoelectric element 201 is radially contracted, so that the vibrating diaphragm 203 protrudes downward, as shown in FIG. 33( a ). As a result, the liquid in the pressurization chamber 211 is pressurized to depress the discharge check valve 205 , thereby forcing the liquid to flow to the discharge port 207 . Next, if the voltage Vssh is fed to the electrode 450 and the voltage Vdd is fed to the electrode 451, the piezoelectric element 201 is radially extended, so that the vibrating diaphragm 203 protrudes upward, as shown in FIG. 33( b ). Then, the liquid in the pressurized chamber 211 is evacuated to push the liquid inlet check valve 204 upward, thereby forcing the liquid to flow from the suction port 206 to the pressurized chamber 211 . In this way, the liquid can be sucked from the suction port 206 to the discharge port 207 by repeating the actions described so far with reference to FIGS. 33( a ) and 33 ( b ).

FIG. 34 is a cross-sectional view showing another embodiment of the structure of the pump unit 101 . The pump assembly is composed of a piezoelectric element 201 , an electrode metal plate 202 , a vibrating diaphragm 203 and a B body 214 . The F main body 290 and the G main body 291 are attached to the underside of the B main body. The F main body is processed with a liquid inlet side valve chamber 208, in which an elastic baffle plate 284 of the liquid inlet check valve, a pressure spring 285 of the liquid inlet side check valve and an elastic retainer for clamping the pressure spring 285 are installed in the valve chamber. Plate 284 is straight and platen 286 is mounted. On the other hand, the G main body 291 is processed with a valve cavity 209 on the discharge side, in which an elastic baffle plate 287 of the check valve on the discharge side, a pressure spring 288 of the check valve on the discharge side and a pressure spring 288 for the discharge side are installed in the valve cavity. The spring 288 clamps the elastic baffle 287 to be straight and the pressing plate 289 installed. An H body 292 processed with a suction port 206 and a discharge port 207 is attached to the underside of the F body 290 and the G body 291 .

Next, a method of assembling will be described below. First, the elastic baffle 284 and the pressure plate 286 are placed in the suction port 206 of the H body 292 , and the F body 290 and the G body 291 are ultrasonically welded to the H body 292 . Thereafter, put the compression spring 285 into the valve chamber 208 at the inlet side, and put the compression spring 288 into the valve chamber 209 at the discharge side. Thereafter, the pressing plate 289 and the elastic baffle 287 are put into the discharge side valve chamber 209 . Then, the B body 214 is welded down to the F body 290 and the G body 291 with ultrasonic waves. Thereafter, the vibrating diaphragm 203 having the piezoelectric element 201 and the electrode metal plate 202 is also ultrasonically welded to the B body, and in this way the pump assembly is assembled.

In this embodiment, resilient baffles 284 and 287 are generally disc-shaped. Platens 286 and 289 are also generally disc-shaped. Compression springs 285 and 288 are further processed into generally cylindrical coil shapes. Here the elastic baffles 284 and 287 are made of silicone rubber or neoprene, but can also be made of another elastic material. The pressure plates 286 and 289 are made of an organic material such as plastic or a metallic material such as stainless steel. The material of the compression springs 285 and 288 should not be limited to metal, and can also be an organic material.

On the other hand, in this embodiment, the compression springs 285 and 288 play the role of clamping the elastic baffles 284 and 287 through the pressure plates 286 and 289, so that the elastic baffles 284 and 287 close the inlet side suction port 212 or (discharge) side) discharge port 213, thereby preventing reverse flow and functioning as a valve. Here, at the contact surface with the elastic baffle 284 (or 287) of the suction port 212 (or the discharge port 213), if the elastic force can be clamped uniformly on the circumference of the suction port 212 (or the discharge port 213), The baffle 284 (287) naturally does not pass through the pressure plate 286 (or 289), but directly clamps the elastic baffle 284 (or 287) by the compression spring 285 (or 288).

35(a) and 35(b) are sectional views illustrating the operation of the pump assembly of FIG. 34. FIG.

If the voltage Vdd is fed to the electrode 450 and the voltage Vssh is fed to the electrode 451, the piezoelectric element 201 contracts radially so that the vibrating diaphragm 203 protrudes downward, as shown in FIG. 35( a ). Then, the liquid in the pressurizing chamber 211 is pressurized beyond the force set by the compression spring 288 . Then, the pressure depresses the elastic flapper 287 , the pressure plate 289 and the compression spring 288 of the discharge side check valve, thus forcing the liquid to flow from the discharge hole 213 through the valve cavity 209 to the discharge port 207 . On the contrary, on the liquid inlet side, push the elastic baffle 284 of the liquid inlet side check valve to compress the suction port 206 through the pressure plate 286 by the action of the compression spring 285, so that there is no reverse flow of liquid from the pressurized chamber 211 to the suction port 206.

Next, if the electrode 450 is fed with the voltage Vssh and the voltage 451 is fed with the voltage Vdd, the piezoelectric element 201 expands radially to make the vibrating diaphragm 203 protrude upward, as shown in FIG. 35( b ). Thus, the liquid in the pressurized chamber 211 is evacuated beyond the force set by the compression spring 285 . Then, the liquid pushes up the elastic baffle 284 , the pressure plate 286 and the compression spring 285 of the liquid inlet check valve, thereby forcing the liquid to flow through the suction port 206 to the valve chamber 208 and to the pressurized chamber 211 through the liquid inlet hole H2. On the contrary, on the discharge side, the elastic baffle 287 of the check valve on the discharge side is pushed, and the discharge hole 213 is compressed by the pressing plate 289 with the help of the compression spring 288, so that no liquid flows from the pressurized chamber 211 to the discharge port. 207 , and there is no liquid flow from the discharge port 207 to the pressurized chamber 211 .

Therefore, by repeating the actions described so far with reference to FIGS. 35( a ) and 35 ( b ), liquid can be forced to flow from the suction port 206 to the discharge port 207 .

FIG. 36 is a sectional view illustrating another embodiment of the pump assembly 101 structure. In this embodiment, a piece of elastic member 293 with a hole 294 is sandwiched between the elastic baffle 284 of the liquid inlet check valve and the suction port 206 . In addition, the elastic member 293 is formed of a stepped disc made of silicone rubber, and is fixedly sandwiched between the F body 290 having the valve cavity 208 and the H body 292 having the suction port 206 .

In the embodiment of Fig. 34, the H body with the suction port 206 is made of plastic and is configured to block backflow by face-to-face contact with the resilient flap 284 of the inlet side check valve. On the other hand, in the embodiment of Fig. 36, the contact surface is made of rubber. As a result, contact can be enhanced to more reliably block backflow. A similar structure is employed on the discharge side.

Fig. 37(a) is a cross-sectional view showing the action of the valve on the inlet side of the pump. As shown, liquid is forced from the suction port 206 through the valve cavity 208 to the inlet port 212 . A gap is established between the elastic baffle plate 284 and the elastic member 293 that are in close contact with each other to allow liquid to pass therethrough by means of the action of the piezoelectric element 201 . Fig. 37(b) is a sectional view showing the operation of the discharge side valve like the liquid intake side valve.

Fig. 38(a) is a sectional view showing another example of the valve structure. In the valve structure of this embodiment, a ridge portion 295 protruding from the periphery of the suction port 206 is formed at the portion where the flapper 284 of the inlet side check valve contacts the suction port 206 . The contact with the baffle plate 284 of the liquid inlet side check valve is changed from a surface to a line, and thus, even a relatively inferior surface contact accuracy can block the reverse flow.

Fig. 38(b) is a cross-sectional view showing the operation of the valve. A space is formed between the ridge portion 295 and the flapper 284 of the liquid inlet side check valve for liquid to pass therebetween. The valve structure on the inlet side described above is also used on the discharge side.

Figure 39 is a cross-sectional view of another embodiment of a valve structure. FIG. 39( a ) shows the structure of the ridge portion 296 protruding around the intake port 206 of the inlet side check valve flapper 284 . Fig. 39(b) shows the operation of the valve constructed in this way. Liquid flow is allowed if a gap is formed between the ridge portion 296 and the suction port 206 .

In the preceding embodiments, the pressure plate 286 (or 289) and the check valve flapper 284 (or 287) are disc-shaped so that they can be superimposed one on top of the other. However, as shown in FIG. 40, if the pressing plate 297 and the check valve damper 298 are configured to engage each other, a stable check valve damper can be realized.

FIG. 41 is a cross-sectional view showing another embodiment of the pump unit structure 101 . This embodiment is structurally in addition to using a ball 501 (and 502) to press the suction port 206 and the discharge hole 213 to replace the non-return valve baffle 284 (or 287) in Figure 34, basically with the referenced figure 34 to describe a similar structure. The spheres to be used here are made of inorganic materials such as steel, ceramic or glass, or organic materials such as plastic or rubber. To insert the pressure plate 286 (or 289) in such a way that the suction port 206 (or the discharge hole 213) can be pushed with a uniform force, and the ball 501 can still be moved if it leaves the suction port 206 (or the discharge hole 213). (or 502) back to the original position (to close the suction port 206 or the drain hole 213). For this reason, the pressure plate 286 (or 289) used is made of a plate having a small coefficient of friction against the balls.

Figure 42(a) shows the action of the inlet side valve of the pump assembly of Figure 41 . The liquid flows through the gap formed between the suction port 206 and the ball 501 . FIG. 42( b ) shows the operation of the discharge side valve of the pump unit of FIG. 41 . Liquid flows through the gap between the drain hole 213 and the ball 502 . In any case, the overall action of the pump is similar to those described with reference to Figures 35(a) and 35(b).

Fig. 43(a) is a sectional view showing another example of the valve structure. Suction port 206 is partially conical in concave contact with ball 501 as indicated at 503 . Since the position of the ball is stabilized by this structure (ie, the ball is guided to the suction port as long as it rolls), a more reliable valve structure can be obtained.

Figure 43(b) shows the flow behavior of the valve structure. If a gap is formed between the ball 501 and the conical portion 503, the liquid also passes through this gap. The structure of the embodiment in Fig. 43 can also be applied to the discharge side valve.

FIG. 44 is a cross-sectional view showing another embodiment of the structure of the pump unit 101 . This embodiment is basically similar to the structure shown in Figure 36, except that the check valve baffle 284 (or 287) is replaced by a ball 501 (or 502). According to this structure, a highly reliable valve can be obtained by virtue of the action of the stepped disk-shaped elastic member 293. Because of the elasticity of the elastic member, even if the ball 501 (or 502) has poor roundness or high hardness and rough surface, the elastic member can make the ball closely contact therewith.

Figures 45(a) and 45(b) show the actions of the balls 501 and 502 at the liquid inlet and discharge sides, the actions shown are the same as those shown in Figures 37(a) and 37(b) or Figures 42(a) and 42( b) similar.

Fig. 46(a) is a sectional view showing another example of the valve structure. The structure is made such that a circular groove 508 is processed around the edge of the contact portion of the liquid inlet hole 206 and the ball 501, and an O-ring 509 is fixed in the groove. The O-ring 509 is made of elastic material such as silicon or neoprene. Therefore, a structure for blocking backflow can be provided by means of close contact between the ball 501 and the O-ring 509 .

FIG. 46( b ) is a cross-sectional view illustrating the operation of the ball valve 501 . As long as there is any gap between the O-ring 509 and the ball 501, liquid will flow through the gap. The valve structure of Fig. 46 is also applicable to the discharge side valve structure.

Fig. 47(a) is a sectional view showing another example of the valve structure. In this embodiment, the ball is not a complete sphere, but a member 510 whose contact surface with the pressure plate 286 is flat and whose contact surface with the liquid inlet hole 206 is hemispherical. Alternatively, the platen 286 and hemispherical member 510 can be adhered to each other so that they can be used as an integral unit. FIG. 47( b ) is a cross-sectional view illustrating the operation of the hemispherical member 510 . As long as there is any gap between the inlet hole 206 and the hemispherical member 510, liquid will flow through the gap. This valve structure of Fig. 47 is also applicable to the discharge side valve structure.

Fig. 48(a) is a sectional view showing another example of the valve structure. This embodiment is configured to use a conical member 511 to compress the liquid inlet hole 206 . It is also possible to glue the conical member 511 and the pressure plate 286 to each other so that they can be used as an integral unit. FIG. 48( b ) is a cross-sectional view illustrating the operation of the conical member 511 . As long as there is any gap between the inlet hole 206 and the conical member 511, liquid will also flow through said gap. The valve structure of Fig. 48 is also applicable to the discharge side valve structure.

Claims (22)

1, a kind of microelectrochemical pump, it comprises: If a piezoelectric element that can be deformed by feeding a control voltage, a vibrating diaphragm having said piezoelectric element adhered thereto so as to be deformable according to deformation of said piezoelectric element, closing of the suction port is released according to the deformation of the vibrating diaphragm in a predetermined direction, a liquid inlet check valve for sucking liquid from the suction port, and A liquid discharge check valve that releases the closure of the radiating hole according to the deformation of the vibrating diaphragm in the above-mentioned opposite direction, and makes the liquid sucked from the suction port radiate from the radiating port through the radiating hole. 2. According to the microelectrochemical pump according to claim 1, it is characterized in that it also includes: The first valve cavity, which is equipped with the liquid inlet check valve and communicates with the suction port, a second valve chamber equipped with the liquid discharge check valve and communicated with the radiation port; and A pressurized chamber defined by the vibrating diaphragm and communicated with the first valve chamber and the second valve chamber through the liquid inlet hole and the discharge hole respectively. 3. According to the microelectrochemical pump according to claim 2, it is characterized in that it also includes: a piece of electrode metal plate bonded between the piezoelectric element and the vibrating diaphragm, a first electrode attached to the piezoelectric element, and A second electrode attached to said electrode metal plate. 4. The microelectrochemical pump according to claim 2, characterized in that: incorporating said inlet check valve and components forming said first valve cavity within a first valve member, and The liquid discharge check valve and the components constituting the second valve chamber are integrated in a second valve member. 5. A microelectrochemical pump according to claim 4, wherein said first valve member and said second valve member are constructed with different valve structures. 6. The microelectrochemical pump according to claim 1, wherein said check valve is fabricated by etching ceramic material. 7. The micro electrochemical pump according to claim 1, characterized in that two or more piezoelectric elements are superimposed on each other and glued together with said vibrating membrane. 8. The microelectrochemical pump according to claim 1, further comprising: a first valve cavity equipped with the liquid inlet check valve and communicated with the suction port and the suction hole; and a second valve cavity equipped with the liquid discharge check valve and communicated with the radiation port and the radiation hole, It is characterized in that the vibrating diaphragm is fixed only at its periphery to close the suction hole and the discharge hole. 9. According to the microelectrochemical pump according to claim 2, it is characterized in that it also includes: a first sealing rubber top cap fitted in the suction inlet, and A second sealing rubber top cover fits over the jet port. 10. The microelectrochemical pump according to claim 2, further comprising: A container connected directly or through a tube to said suction port, a first sealing rubber top cap fitted in the container opening, and A second sealing rubber top cover fits over the jet port. 11. The micro electrochemical pump according to claim 2, characterized in that said vibrating diaphragm comprises: An electrode metal plate having at least one tapered hole in its thickness direction, and a plastic plate fixed to the electrode metal plate by filling the tapered hole. 12. The microelectrochemical pump according to claim 11, wherein said plastic plate is processed with an annular protrusion for positioning said piezoelectric element. 13. The microelectrochemical pump according to claim 11, characterized in that said electrode metal plate is processed with a welded protruding part on its part, and the protruding part does not overlap with the plane of said plastic flat plate. 14. The microelectrochemical pump according to claim 11, characterized in that said vibrating diaphragm is processed with an ultrasonic solvent welding protruding piece around the plastic surface of the other side of said plastic flat plate in contact with said electrode metal plate. 15. The microelectrochemical pump according to claim 1, further comprising: a liquid inlet check valve comprising a first elastic flap for closing said suction port and a first spring member for elastically pushing said first elastic flap, and A liquid inlet check valve comprising a second elastic baffle for closing the radiating hole and a second spring member for elastically pushing the second elastic baffle. 16. The microelectrochemical pump according to claim 1, characterized in that: The liquid inlet check valve includes: a first member having an arc portion for closing the suction port and a first spring member for elastically pushing the first member, and The liquid discharge check valve includes a second member having an arc portion for closing the radiating hole, and a second spring member for elastically pushing the second member. 17. The microelectrochemical pump according to claim 1, further comprising: an integrated circuit for applying a control voltage to said piezoelectric element, and A power source for operating the integrated circuit. 18. A micro-radiation device comprising: A pump assembly that discharges liquid at a minute rate based on the displacement of the vibrating diaphragm that deforms with the deformation of the piezoelectric element, a control circuit unit for operating and controlling said pump assembly, and a power supply unit for supplying power to said pump assembly and said control circuit unit, It is characterized in that the pump assembly, the control circuit unit and the power supply unit are all housed in a casing. 19. A microradiation device according to claim 18, further comprising: A display disposed outside the housing of the microradiation device. 20. A microradiation device according to claim 18, further comprising: A container disposed in the housing of the microirradiation device for supplying liquid to the pump assembly. 21. The microradiation device according to claim 18, further comprising: A syringe needle provided outside the housing of the micro-irradiation device and connected to the injection port of the pump assembly. 22. A microradiation device according to claim 18, wherein said power supply means comprises a battery.

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