US20040146409A1 - Micro-pump driven by phase change of a fluid - Google Patents

Micro-pump driven by phase change of a fluid Download PDF

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Publication number
US20040146409A1
US20040146409A1 US10/757,392 US75739204A US2004146409A1 US 20040146409 A1 US20040146409 A1 US 20040146409A1 US 75739204 A US75739204 A US 75739204A US 2004146409 A1 US2004146409 A1 US 2004146409A1
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United States
Prior art keywords
fluid
pumping chamber
micro
pump
entrance
Prior art date
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Abandoned
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US10/757,392
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English (en)
Inventor
You-Seop Lee
Yong-soo Oh
Keon Kuk
Min-Soo Kim
Seung-joo Shin
Su-Ho Shin
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Filing date
Publication date
Application filed by Samsung Electronics Co Ltd filed Critical Samsung Electronics Co Ltd
Assigned to SAMSUNG ELECTRONICS CO., LTD. reassignment SAMSUNG ELECTRONICS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KIM, MIN-SOO, KUK, KEON, LEE, YOU-SEOP, OH, YONG-SOO, SHIN, SEUNG-JOO, SHIN, SU-HO
Publication of US20040146409A1 publication Critical patent/US20040146409A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B19/00—Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
    • F04B19/006—Micropumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B19/00—Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
    • F04B19/20—Other positive-displacement pumps
    • F04B19/24—Pumping by heat expansion of pumped fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B43/00—Machines, pumps, or pumping installations having flexible working members
    • F04B43/0009—Special features
    • F04B43/0027—Special features without valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/08—Cooling; Heating; Preventing freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/10—Valves; Arrangement of valves
    • F04B53/1077—Flow resistance valves, e.g. without moving parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2210/00—Working fluid
    • F05B2210/10—Kind or type
    • F05B2210/11—Kind or type liquid, i.e. incompressible
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S417/00—Pumps

Definitions

  • the present invention relates to a micro-pump. More particularly, the present invention relates to a micro-pump driven by a phase change of a fluid.
  • MEMS micro electro mechanical systems
  • FIGS. 1A and 1B illustrate cross-sectional views of a conventional micro-pump having check valves.
  • the conventional micro-pump is driven by a piezoelectric body 12 attached to an upper film of a pumping chamber 10 .
  • a fluid entrance 14 and a fluid exit 16 are connected to the pumping chamber 10 , and first and second check valves 15 and 17 are provided at the interface between the fluid entrance 14 and the pumping chamber 10 and at the interface between the fluid exit 16 and the pumping chamber 10 , respectively.
  • first and second check valves 15 and 17 are provided at the interface between the fluid entrance 14 and the pumping chamber 10 and at the interface between the fluid exit 16 and the pumping chamber 10 , respectively.
  • FIG. 1A when the piezoelectric body 12 is transformed due to a voltage applied thereto, the volume of the pumping chamber 10 increases.
  • the second check valve 17 is shut and the first check valve 15 is opened so that a fluid can be supplied into the pumping chamber 10 through the fluid entrance 14 .
  • the first check valve 15 is shut, and the second check valve 17 is opened. Accordingly, a small amount of fluid is discharged through the fluid exit 16 .
  • the check valves 15 and 17 which induce the flow of a fluid in one direction, are intended to operate in a tiny structure. Pumps and valves used in MEMS devices, in particular, are required to have a very small size. Therefore, due to the sizes thereof, the check valves 15 and 17 are not suitable for application in MEMS devices. Even if the check valves 15 and 17 are implemented in a MEMS device, it is difficult to guarantee the durability of the check valves 15 and 17 for any required predetermined time period. In addition, due to the mass inertia of the check valves 15 and 17 , the check valves 15 and 17 may not operate well at high frequencies.
  • FIG. 2 illustrates a cross-sectional view of another conventional micro-pump.
  • the conventional micro-pump does not have movable elements as the check valves 15 and 17 of FIGS. 1A and 1B.
  • the conventional micro-pump of FIG. 2 includes a pair of fluid passages 22 and 23 , which are pyramid-shaped.
  • the fluid passages 22 and 23 are connected to a lower part of a pumping chamber 20 so that they extend along different directions.
  • a piezoelectric body 21 is installed at an upper film of the pumping chamber 20 as a driving means.
  • the fluid passage 22 has such a structure that a cross-sectional area thereof decreases along a direction toward the pumping chamber 20 .
  • the fluid passage 23 has such a structure that a cross-sectional area thereof increases along the direction toward the pumping chamber 20 .
  • the fluid passage 22 or 23 is formed with a relatively large inclination angle of about 50-70°, flux resistance in a direction along which the cross-sectional area of the fluid passage 22 or 23 decreases is smaller than flux resistance in a direction along which the cross-sectional area of the fluid passage 22 or 23 increases. Accordingly, fluids respectively passing through the fluid passages 22 and 23 are affected by different levels of flux resistance due to volume variations in the pumping chamber 20 caused by vibration of the piezoelectric body 21 .
  • the conventional micro-pump of FIG. 2 enables a net flow rate in a direction in which fluid is pumped out, without the need for check valves.
  • FIGS. 3A and 3B illustrate cross-sectional views of still another conventional micro-pump.
  • the conventional micro-pump of FIGS. 3A and 3B does not have valves. Rather, the conventional micro-pump of FIGS. 3A and 3B includes a pair of fluid passages, i.e., a fluid exit 33 and a fluid entrance 34 , having cross-sectional areas that vary along a direction in which a fluid is pumped.
  • the fluid exit 33 and the fluid entrance 34 are connected to opposite sides of a pumping chamber 30 , and a piezoelectric membrane 32 is provided on the pumping chamber 30 as a driving means.
  • a cross-sectional area of the fluid entrance 34 increases in a direction toward the pumping chamber 30
  • a cross-sectional area of the fluid exit 33 decreases in a direction toward the pumping chamber 30 .
  • the fluid passages 33 and 34 are formed with a relatively small inclination angle of about 15-30°, flux resistance in a direction of increasing cross-sectional area of the fluid passages 33 and 34 is smaller than flux resistance in a direction of decreasing cross-sectional area of the fluid passages 33 and 34 . Therefore, as shown in FIG. 3A, when a fluid is pumped into the pumping chamber 30 due to a transformation of the piezoelectric membrane 32 , an amount of fluid passing through the fluid entrance 34 is larger than an amount of fluid passing through the fluid exit 33 . However, as shown in FIG. 3B, when the fluid is discharged from the pumping chamber 30 , the amount of fluid passing through the fluid exit 33 is much larger than the amount of fluid passing through the fluid entrance 34 .
  • the conventional micro-pump of FIGS. 3A and 3B generates a net flow rate in a direction in which the fluid is pumped due to a difference between the flux resistance in the direction of increasing cross-sectional area of the fluid passages 33 and 34 and the flux resistance in the direction of decreasing cross-sectional area of the fluid passages 33 and 34 .
  • the above-mentioned conventional micro-pumps generate a net flow rate by taking advantage of a variation of the volume of a pumping chamber caused by vibrations of a piezoelectric body.
  • the piezoelectric body having a complex structure, is relatively difficult to manufacture.
  • the area of the piezoelectric body should be increased.
  • a pumping flow rate can be increased by increasing the volume of a pumping chamber. In this case, however, the degree to which an upper film of the pumping chamber is transformed due to vibrations of the piezoelectric body should be enlarged, which may result in a high possibility of serious damage to the upper film.
  • the present invention provides a micro-pump having a relatively simple structure, but which shows enhanced durability and high pumping efficiency without the need for movable elements by pumping out a fluid supplied into a pumping chamber by simply taking advantage of a phase change of the fluid.
  • a micro-pump including a pumping chamber having a predetermined inner space to be filled with a fluid, at least one fluid entrance and at least one fluid exit, which are connected to the pumping chamber, a heating element provided at one side of the pumping chamber to generate bubbles in the pumping chamber by heating the fluid, and electrodes for applying current to the heating element, wherein the fluid is made to flow into or out of the pumping chamber by expansion and contraction of the bubbles, and wherein a cross-sectional area of at least one of the fluid entrance and the fluid exit varies along a direction in which the fluid flows.
  • the cross-sectional area of the fluid entrance decreases in a direction toward the pumping chamber, and the cross-sectional area of the fluid exit increases in a direction toward the pumping chamber.
  • the fluid entrance and the fluid exit are formed to have an inclination angle of at least about 50°.
  • the cross-sectional area of the fluid entrance increases in a direction toward the pumping chamber, and the cross-sectional area of the fluid exit decreases in a direction toward the pumping chamber.
  • the fluid entrance and the fluid exit are respectively formed to have an inclination angle of about 30° or less.
  • the fluid entrance is provided at one side of the pumping chamber and the fluid exit is provided at an opposite side of the pumping chamber to face the fluid entrance.
  • the fluid entrance and the fluid exit each have a pyramid shape.
  • the fluid entrance and the fluid exit each have a uniform height and a width that varies in a direction in which the fluid flows.
  • the pumping chamber and the heating element each have a rectangular shape.
  • the pumping chamber and the heating element each have a circular shape.
  • the heating element is formed of a resistive heating material.
  • the micro-pump may further include a substrate in which the pumping chamber, the fluid entrance, and the fluid exit are formed.
  • the micro-pump may further include an insulation layer formed on the substrate, wherein the insulation layer constitutes an upper wall of the pumping chamber, and the heating element and the electrodes are formed on the insulation layer.
  • the micro-pump may further include a passivation layer having insulation characteristics formed on the heating element and the electrodes.
  • the micro-pump may further include a heat dissipation layer formed on the passivation layer for dissipating heat, wherein the heat dissipation layer is connected to the substrate.
  • the heat dissipation layer is formed of a metal.
  • FIGS. 1A and 1B respectively illustrate cross-sectional views of a fluid supply mode and a fluid pumping mode of a conventional micro-pump;
  • FIG. 2 illustrates a cross-sectional view of another conventional micro-pump
  • FIGS. 3A and 3B respectively illustrate cross-sectional views of a fluid supply mode and a fluid pumping mode of still another conventional micro-pump;
  • FIG. 4A illustrates a plan view of a micro-pump according to a first embodiment of the present invention
  • FIG. 4B illustrates a cross-sectional view of the micro-pump according to the first embodiment of the present invention taken along line A-A′ of FIG. 4A;
  • FIG. 4C illustrates a cross-sectional view of the micro-pump according to the first embodiment of the present invention taken along line B-B′ of FIG. 4A;
  • FIGS. 5A and 5B respectively illustrate cross-sectional views of a fluid pumping mode and a fluid supply mode of the micro-pump according to the first embodiment of the present invention
  • FIG. 6A illustrates a plan view of a micro-pump according to a second embodiment of the present invention
  • FIG. 6B illustrates a cross-sectional view of the micro-pump according to the second embodiment of the present invention taken along line C-C′ of FIG. 6A;
  • FIGS. 7A and 7B respectively illustrate cross-sectional views of a fluid pumping mode and a fluid supply mode of the micro-pump according to the second embodiment of the present invention.
  • FIGS. 8A through 8C are graphs illustrating characteristics of a micro-pump according to an embodiment of the present invention.
  • FIG. 4A illustrates a plan view of a micro-pump according to a first embodiment of the present invention.
  • FIG. 4B illustrates a cross-sectional view of the micro-pump according to the first embodiment of the present invention taken along line A-A′ of FIG. 4A.
  • FIG. 4C illustrates a cross-sectional view of the micro-pump according to the first embodiment of the present invention taken along line B-B′ of FIG. 4A.
  • a micro-pump according to a first embodiment of the present invention includes a pumping chamber 112 , which has a predetermined inner space so that it can be filled with a fluid, a fluid entrance 113 and a fluid exit 114 , which are connected to the pumping chamber 112 , a heating element 130 , which is provided at one side of the pumping chamber 112 , and electrodes 151 and 152 , which apply current to the heating element 130 .
  • the pumping chamber 112 has a rectangular shape, and the predetermined inner space of the pumping chamber 112 has a rectangular hexahedral shape.
  • a driving force is applied to a fluid supplied into the pumping chamber 112 via the fluid entrance 113 to thereby discharge the fluid through the fluid exit 114 .
  • the fluid entrance 113 which is provided between an inlet manifold 115 and the pumping chamber 112 , supplies a fluid from the inlet manifold 115 into the pumping chamber 112 .
  • the fluid exit 114 which is provided between an outlet manifold 116 and the pumping chamber 112 , discharges a fluid from the pumping chamber 112 to the outlet manifold 116 .
  • a plurality of fluid entrances and a plurality of fluid exits may be provided to the micro-pump.
  • the fluid entrance 113 is provided at one side of the pumping chamber 112 and the fluid exit 114 is provided at an opposite side of the pumping chamber 112 so that the fluid exit 114 faces the fluid entrance 113 .
  • the fluid entrance 113 and the fluid exit 114 may be arranged differently.
  • the fluid entrance 113 and the fluid exit 114 may be arranged together at one side of the pumping chamber 112 or under the pumping chamber 112 .
  • the fluid entrance 113 has a decreasing cross-sectional area in a direction toward the pumping chamber 112
  • the fluid exit 114 has an increasing cross-sectional area in a direction toward the pumping chamber 112
  • the fluid entrance 113 and the fluid exit 114 preferably have an inclination angle ⁇ of at least about 50°, for example, an inclination angle of about 50-70°. Then, flux resistance affecting a fluid passing through the fluid entrance 113 and the fluid exit 114 varies depending on the flow direction of the fluid.
  • flux resistance in a direction in which the cross-sectional area of the fluid entrance 113 and the cross-sectional area of the fluid exit 114 decreases is smaller than flux resistance in a direction in which the cross-sectional area of the fluid entrance 113 and the cross-sectional area of the flow exit 114 increases. Due to a difference between the flux resistance in the direction of decreasing cross-sectional area of the fluid entrance 113 and the fluid exit 114 and the flux resistance in the direction of increasing cross-sectional area of the fluid entrance 113 and the flow exit 114 , a net flow rate can be generated in a direction in which the fluid is pumped without the need for check valves, which will be described more fully later.
  • the fluid entrance 113 and the fluid exit 114 may have a pyramid shape, as shown in FIGS. 4A and 4B, so that the cross-sectional areas thereof decrease along the direction in which the fluid is pumped.
  • each of the fluid entrance 113 and the fluid exit 114 may have a uniform height but a decreasing width along the direction in which the fluid is pumped.
  • the fluid entrance 113 and the fluid exit 114 may have a different shape, such as a polygonal or circular cross-section, provided they meet the above-mentioned requirements.
  • Both the fluid entrance 113 and the fluid exit 114 have been described so far as having a varying cross-sectional area along a certain direction. However, it is possible to achieve a net flow rate by forming only one of the fluid entrance 113 and the fluid exit 114 to have a varying cross-sectional area along a certain direction.
  • the pumping chamber 112 , the fluid entrance 113 , the fluid exit 114 , and the inlet and outlet manifolds 115 and 116 may be formed by micro-machining a substrate 110 in a variety of ways.
  • the pumping chamber 112 , the fluid entrance 113 , the fluid exit 114 , and the inlet and outlet manifolds 115 and 116 are formed by etching the surface of the substrate 110 to a predetermined depth, in which case the fluid entrance 113 and the fluid exit 114 may be formed on the substrate 110 to a predetermined depth, to be connected to an upper portion of the pumping chamber 112 .
  • An insulation layer 120 is formed on the substrate 110 , and forms an upper wall of the pumping chamber 112 .
  • the heating element 130 is formed on the insulation layer 120 .
  • the heating element 130 generates bubbles in the pumping chamber 112 by heating the fluid in the pumping chamber 112 . Expansions and contractions of the bubbles cause the fluid to flow.
  • the heating element 130 may be formed of a resistive heating element, such as an alloy of tantalum and aluminium or tantalum nitride. As shown in FIG. 4A, the heating element 130 , like the pumping chamber 112 , preferably has a rectangular shape. The heating element 130 , however, may have a different shape.
  • a first passivation layer 140 which has insulation characteristics, is formed on the heating element 130 and the insulation layer 120 , and the electrodes 151 and 152 are formed on the first passivation layer 140 .
  • the electrodes 151 and 152 are connected to the heating element 130 at either side of the heating element 130 through a contact hole C, formed in the first passivation layer 140 .
  • a second passivation layer 160 which has insulation characteristics, is formed on the first passivation layer 140 and the electrodes 151 and 152 , and a heat dissipation layer 170 may be formed on the second passivation layer 160 .
  • the heat dissipation layer 170 is connected to the substrate 110 through a second contact hole C 2 , which is formed through the first and second passivation layers 140 and 160 and the insulation layer 120 .
  • the heat dissipation layer 170 is provided for dissipating heat of the heating element 130 or other elements near the heating element 130 to the substrate 110 or to the outside.
  • the heat dissipation layer 170 may be formed of a metal having superior heat conductivity.
  • FIGS. 5A and 5B respectively illustrate cross-sectional views of a fluid pumping mode and a fluid supply mode of the micro-pump according to the first embodiment of the present invention.
  • the pumping chamber 112 is filled with a fluid 180 .
  • a pulse-type current signal is applied to the heating element 130 via the electrodes 151 and 152 , the heating element 130 generates heat to heat the fluid 180 in the pumping chamber 112 via the insulation layer 120 .
  • the fluid 180 is heated to a predetermined temperature or higher, the fluid 180 boils, and accordingly, a bubble 190 is generated. Since the bubble 190 is in a gas phase with high pressure, it expands pushing out nearby fluid 180 . Due to the expansion of the bubble 190 , the fluid 180 in the pumping chamber 112 is discharged to the outlet manifold 116 through the fluid exit 114 , during which the current signal applied to the heating element 130 is removed.
  • the expansion of the bubble 190 also generates a flow rate in the opposite direction by causing the fluid 180 to flow to the inlet manifold 115 through the fluid entrance 113 . Since flux resistance in a direction of decreasing cross-sectional area of the fluid entrance 113 and the fluid exit 114 is smaller than flux resistance in a direction of increasing cross-sectional area of the fluid entrance 113 and the fluid exit 114 , the amount of fluid discharged through the fluid exit 114 is much larger than the amount of fluid discharged through the fluid entrance 113 .
  • the bubble 190 contracts and disappears after expanding to its maximum size. Then, pressure affects the pumping chamber 112 in a direction from outside the pumping chamber 112 to the inside of the pumping chamber 112 . Accordingly, the fluid flows into the pumping chamber 112 through both the fluid entrance 113 and the fluid exit 114 . In this case, flux resistance at the fluid entrance 113 is smaller than flux resistance at the fluid exit 114 . Thus, the amount of fluid flowing into the pumping chamber 112 through the fluid entrance 113 is much larger than the amount of fluid flowing into the pumping chamber through the fluid exit 114 .
  • heat generated by the heating element 130 to generate the bubble 190 is dissipated to the substrate 110 and to the outside via the heat dissipation layer 170 . Due to the existence of the heat dissipation layer 170 , heat can be more quickly dissipated. Thus, a cycle of expansion and contraction that the bubble 190 undergoes becomes shorter, and the driving frequency of the micro-pump is increased.
  • the bubble 190 when the bubble 190 expands, the amount of fluid 180 discharged from the pumping chamber 112 through the fluid exit 114 is much larger than the amount of fluid 180 discharged from the pumping chamber 112 through the fluid entrance 113 .
  • the bubble 190 contracts, however, the amount of fluid 180 flowing into the pumping chamber 112 through the fluid entrance 113 is much larger than the amount of fluid 180 flowing into the pumping chamber 112 through the fluid exit 114 . Therefore, if the bubble 190 repeatedly undergoes a cycle of expansion and contraction with a predetermined frequency, a net flow rate in a direction from the fluid entrance 113 to the pumping chamber 112 to the fluid exit 114 can be generated, and desired pumping effects can be achieved.
  • the heating element 130 provides a driving force for pumping the fluid 180 , and the fluid entrance 113 and exit 114 serve as dynamic passive valves.
  • the fluid entrance 113 and exit 114 serve as dynamic passive valves.
  • FIG. 6A illustrates a plan view of a micro-pump according to a second embodiment of the present invention.
  • FIG. 6B illustrates a cross-sectional view of the micro-pump according to the second embodiment of the present invention taken along line C-C′ of FIG. 6A.
  • FIG. 6A only features of the present invention that are different from their counterparts in the first embodiment of the present invention are illustrated for convenience of the drawing.
  • the second embodiment of the present invention is the same as the first embodiment of the present invention except in a shape of a pumping chamber 212 , a heating element 230 , and fluid passages 213 and 214 .
  • a micro-pump according to a second embodiment of the present invention includes the pumping chamber 212 , which has a circular shape.
  • An inner space of the pumping chamber 212 may have a hemispherical or cylindrical shape.
  • the heating element 230 preferably has a circular shape, as shown in FIG. 6A.
  • the fluid passages 213 and 214 i.e., a fluid entrance 213 and a fluid exit 214 , are formed to extend relatively very long. Thus, it is difficult to form the fluid passages 213 and 214 to have a relatively large inclination angle.
  • the fluid entrance 213 has an increasing cross-sectional area in a direction toward the pumping chamber 212
  • the fluid exit 214 has a decreasing cross-sectional area in a direction toward the pumping chamber 212
  • the fluid entrance 213 and the fluid exit 214 are preferably formed to have a relatively small inclination angle ⁇ of about 15-30°. Due to the existence of the fluid passages 213 and 214 , flux resistance in a direction of gradually increasing cross-sectional area of the fluid passages 213 and 214 is smaller than flux resistance in a direction of gradually decreasing cross-sectional area of the fluid passages 213 and 214 , which will be described more fully later.
  • the fluid passages 213 and 214 may have different shapes provided they meet the above-mentioned requirements. In the present embodiment, like in the previous embodiment, it is possible to form only one of the fluid passages 213 and 214 to have a gradually decreasing or gradually increasing cross-sectional area.
  • the pumping chamber 212 , the fluid entrance 213 , the fluid exit 214 , and inlet and outlet manifolds 215 and 216 are formed by etching a surface of a substrate 210 to a predetermined depth, in which case the fluid passages 213 and 214 are preferably formed to have a uniform height but an increasing width in a direction along which a fluid is pumped.
  • An insulation layer 220 , a heating element 230 , a first passivation layer 240 , electrodes 251 and 252 , a second passivation layer 260 , and a heat dissipation layer 270 formed on the substrate 210 are the same as their counterparts in the first embodiment of the present invention, and thus their description will not be repeated.
  • FIG. 7A illustrates a fluid pumping mode
  • FIG. 7B illustrates a fluid supply mode
  • a pulse-type current signal is applied to the heating element 230 via the electrodes 251 and 252 . Then, heat is generated by the heating element 230 . The generated heat heats a fluid 280 inside the pumping chamber 212 so that a bubble 290 is generated. Due to expansion of the bubble 290 , the fluid 280 in the pumping chamber 212 is discharged from the pumping chamber 212 to the outlet manifold 216 through the fluid exit 214 , during which the pulse-type current signal applied to the heating element 230 is removed. As the bubble 290 expands, a flow rate of the fluid 280 is generated in a direction toward the inlet manifold 215 via the fluid entrance 213 .
  • the micro-pump according to the second embodiment of the present invention provides a similar pumping effect as that of the micro-pump according to the first embodiment of the present invention.
  • the micro-pump according to the second embodiment of the present invention does not need a movable element, it is possible to manufacture a micro-pump having a relatively simple structure and enhanced durability, in which a pumping flow rate may be easily enhanced.
  • FIGS. 8A through 8C are graphs illustrating characteristics of a micro-pump according to an embodiment of the present invention. More specifically, FIG. 8A is a graph illustrating a variation of an amount of fluid passing through a fluid exit in accordance with a passage of time. FIG. 8B is a graph illustrating a variation of an amount of fluid passing through a fluid entrance in accordance with a passage of time. FIG. 8C is a graph illustrating a variation of a net flow rate of fluid in accordance with a passage of time.
  • the fluid entrance and the fluid exit are circular-shaped having an average diameter of 28 ⁇ m and a length of 30 ⁇ m, and having a decreasing cross-sectional area in a direction in which fluid is pumped.
  • the variation of the amount of fluid passing through the fluid entrance or the fluid exit in accordance with the passage of time (s) was measured while carrying out a 20 kHz pumping process for six cycles, i.e., for about 300 ⁇ s.
  • a positive amount of fluid passing through the fluid entrance or the fluid exit represents the volume of fluid flowing out of a pumping chamber into a manifold
  • a negative amount of fluid passing through the fluid entrance or the fluid exit represents the volume of fluid flowing into the pumping chamber from the manifold.
  • 1 ⁇ 10 ⁇ 14 m 3 is equal to 10 pl.
  • a time when fluid passes through the fluid entrance corresponds to a time when fluid passes through the fluid exit, which correspond to cycles of appearance and then disappearance of bubbles in the fluid.
  • the amount of the fluid passing through the fluid entrance is different from the amount of the fluid passing through the fluid exit.
  • the sum of the amount of the fluid passing through the fluid entrance and the amount of the fluid passing through the fluid exit is the amount of the fluid flowing into or flowing out of the pumping chamber through the fluid entrance or the fluid exit.
  • a net flow rate exists along a direction from the fluid entrance to the fluid exit, which is illustrated in the graph of FIG. 8C.
  • This amount of fluid pumped per cycle may be increased by adjusting a shape and an inclination angle of the fluid entrance and/or the fluid exit.
  • pumping effects may be maximized by increasing a driving frequency.
  • a fluid can be pumped in accordance with a phase change of the fluid flowing into a pumping chamber.
  • a micro-pump according to the embodiments of the present invention does not require a movable element to allow fluid to flow. Therefore, according to the present invention, it is possible to realize a micro-pump having.
  • it is possible to easily enhance a pumping efficiency of a micro-pump of the present invention by increasing an area of a heating element provided at one side of a pumping chamber or by increasing caloric power of the heating element.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Micromachines (AREA)
  • Jet Pumps And Other Pumps (AREA)
US10/757,392 2003-01-15 2004-01-15 Micro-pump driven by phase change of a fluid Abandoned US20040146409A1 (en)

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KR10-2003-0002727A KR100499141B1 (ko) 2003-01-15 2003-01-15 유체의 상변화에 의해 구동되는 마이크로 펌프
KR2003-2727 2003-01-15

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US (1) US20040146409A1 (de)
EP (1) EP1439307B1 (de)
JP (1) JP2004218644A (de)
KR (1) KR100499141B1 (de)
DE (1) DE602004005506T2 (de)

Cited By (11)

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US20070170813A1 (en) * 2005-03-03 2007-07-26 Ryouichi Takayama Surface acoustic wave device and method of manufacturing the same
WO2008150210A1 (en) * 2007-06-07 2008-12-11 Ge Healthcare Bio-Sciences Ab Micropump
US20100158720A1 (en) * 2005-07-27 2010-06-24 Koji Miyazaki Valveless micropump
US20100239436A1 (en) * 2005-05-17 2010-09-23 Honeywell International Inc. A thermal pump
CN103016287A (zh) * 2012-12-31 2013-04-03 北京工业大学 感应加热相变式微喷驱动器
CN103967740A (zh) * 2014-04-12 2014-08-06 北京工业大学 感应加热的汽泡驱动微泵
US9291172B2 (en) 2012-11-29 2016-03-22 Korea Institute Of Science And Technology Apparatus and method for generating wave functional pulsatile microflows by applying Fourier cosine series and hydraulic head difference
WO2017118895A1 (en) * 2016-01-05 2017-07-13 Funai Electric Co., Ltd. Microfluidic pump with thermal control
CN107605713A (zh) * 2017-10-26 2018-01-19 电子科技大学 一种大流量的无阀微泵
US10197188B2 (en) 2014-08-15 2019-02-05 Hewlett-Packard Development Company, L.P. Microfluidic valve

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CN101975153B (zh) * 2010-10-12 2012-07-04 江苏大学 椭圆组合管无阀压电泵
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DE102011115622A1 (de) * 2010-12-20 2012-06-21 Technische Universität Ilmenau Mikropumpe sowie Vorrichtung und Verfahren zur Erzeugung einer Fluidströmung
CN109139406B (zh) * 2018-07-13 2019-10-01 江苏大学 一种基于微流控技术的热驱动微泵实验装置与方法
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WO2023223556A1 (ja) * 2022-05-20 2023-11-23 三菱電機株式会社 液流発生装置

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US20070170813A1 (en) * 2005-03-03 2007-07-26 Ryouichi Takayama Surface acoustic wave device and method of manufacturing the same
WO2006121534A1 (en) * 2005-05-09 2006-11-16 University Of Oregon Thermally-powered nonmechanical fluid pumps using ratcheted channels
US20100239436A1 (en) * 2005-05-17 2010-09-23 Honeywell International Inc. A thermal pump
US20100158720A1 (en) * 2005-07-27 2010-06-24 Koji Miyazaki Valveless micropump
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WO2008150210A1 (en) * 2007-06-07 2008-12-11 Ge Healthcare Bio-Sciences Ab Micropump
US9291172B2 (en) 2012-11-29 2016-03-22 Korea Institute Of Science And Technology Apparatus and method for generating wave functional pulsatile microflows by applying Fourier cosine series and hydraulic head difference
CN103016287A (zh) * 2012-12-31 2013-04-03 北京工业大学 感应加热相变式微喷驱动器
CN103967740A (zh) * 2014-04-12 2014-08-06 北京工业大学 感应加热的汽泡驱动微泵
US10197188B2 (en) 2014-08-15 2019-02-05 Hewlett-Packard Development Company, L.P. Microfluidic valve
WO2017118895A1 (en) * 2016-01-05 2017-07-13 Funai Electric Co., Ltd. Microfluidic pump with thermal control
CN107605713A (zh) * 2017-10-26 2018-01-19 电子科技大学 一种大流量的无阀微泵

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KR100499141B1 (ko) 2005-07-04
EP1439307A1 (de) 2004-07-21
KR20040065647A (ko) 2004-07-23
JP2004218644A (ja) 2004-08-05
DE602004005506D1 (de) 2007-05-10
EP1439307B1 (de) 2007-03-28
DE602004005506T2 (de) 2008-01-24

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