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Micro-pumpRelated Patent Categories: Pumps, Motor Driven, Fluid Motor, Common Pumping And Motor Working Member, Collapsible Common Member, DiaphragmMicro-pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080063543, Micro-pump. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation application of U.S. utility application Ser. No. 10/676,601 filed Oct. 1, 2003 entitled Micro-pump. BACKGROUND [0002] This invention relates to a micro-pump (or miniature pump) that is suitable for use in biomedical and bio-analytical applications. [0003] Micro-pumps have recently been of interest and found applications, for example, in the life sciences and the pharmaceutical sector. One application is the delivery of drugs to the human body. For this purpose, micro-pumps are worn on the human body or implanted therein. Micro-pumps are also used in bio-analytical or biochemical research. [0004] One of the driving factors for the increase in bio-analysis applications is the completion of the Human Genome Project, which results in the rapid development of molecular diagnostics in the laboratories. Diagnostic systems used in these laboratories include micro-pumps which are essential for micro-fluid manipulation of reagent and fluid samples. These micro-pumps, with integrated micro-valves, are capable of precise and controllable fluid delivery in the range of .mu.l/min to ml/min. To avoid contamination, most components in a diagnostic system, including micro-pumps, are typically disposed after each use. Consequently, a micro-pump for use in such a diagnostic system should ideally be low in cost, reliable and easy to control. [0005] Various types of micro-pumps are available. Some of these micro-pumps are described in U.S. Patent Application 2002/0081866, Choi et al., "Thermally Driven Micro-pump Buried In A Silicon Substrate And Method For Fabricating The Same"; U.S. Pat. No. 6,390,791, Maillefer et al., "Micro Pump Comprising an Inlet Control Member For Its Self-Priming"; U.S. Pat. No. 5,759,014, Van Lintel, "Micro-pump"; U.S. Pat. No. 5,499,909, Yamada et al., "Pneumatically Driven Micro-pump"; U.S. Pat. No. 6,520,753, Grosjean et al., "Planar Micro-pump"; U.S. Pat. No. 6,408,878, Unger et al., "Microfabricated Elastomeric Valve And Pump Systems"; WO 02/43615, Unger et al., "Microfabricated Elastomeric Valve And Pump Systems"; Didier Maillefer et al., "A High-Performance Silicon Micro-pump For Disposable Drug Delivery Systems", The thirteenth IEEE International Micro Electro Mechanical Systems (MEMS-2000) Conference, Miyazaki, Japan; Melvin Khoo et al., "A Novel Micromachined Magnetic Membrane Microfluid Pump", The 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Chicago, Ill., 2000; R. Linnemann, P. Woias, C. D. Senffl, and J. A. Ditterich, "A self-priming and bubble tolerant piezoelectric silicon micro-pump for liquids and gases", The 11.sup.th annual international workshop on MEMS. 1998, Heidelberg Germany, pp. 532-537; K. P. Kamper, J. Dopper, W. Ehrfeld, and S. Oberbeck, "A self-filling low-cost membrane micro-pump", The 11.sup.th annual international workshop on MEMS. 1998, Heidelberg Germany, pp. 432-437; Jun Shinohara et al., "A high pressure-resistance micro-pump using active and normally-closed valves", Thirteenth IEEE International Micro Electro Mechanical Systems (MEMS-2000) Conference. Miyazaki, Japan, 2000; Charles Grosjean et al., "A thermopneumatic peristaltic micro-pump", Technical Digest of Transducers '99, Sendai, Japan; and Didier Maillefer et al., "A high-performance silicon micro-pump for an implantable drug delivery system", The 1999 IEEE International Micro Electro Mechanical Systems (MEMS 1999) Conference. Orlando, Fla., USA, 1999. [0006] Some of the micro-pumps generally include a diaphragm in a chamber that is bounded either by two check valves or two nozzle/diffuser configurations. Such micro-pumps are disclosed in U.S. Pat. No. 5,759,014, U.S. Pat. No. 6,390,791, and Didier Maillefer et al., "A High-Performance Silicon Micro-pump For Disposable Drug Delivery Systems", The thirteenth IEEE International Micro Electro Mechanical Systems (MEMS-2000) Conference, Miyazaki, Japan. The diaphragm of these micro-pumps is typically fabricated from a silicon wafer using bulk micro-machining or surface micro-machining. Bulk micro-machining is a subtractive fabrication method whereby single crystal silicon is lithographically patterned and then etched to form three-dimensional structures. Surface micro-machining is an additive method where layers of semiconductor-type materials such as polysilicon, silicon nitrate, silicon dioxide, and various suitable metals are sequentially added and patterned to make three-dimensional structures. The use of either of the above methods requires clean room facilities and careful quality control processes. Consequently, the micro-pumps including the silicon diaphragm are high in material cost and expensive to manufacture. The high cost may be prohibitive for disposable use. A cheaper alternative to these micro-pumps is thus desirable, especially for disposable use in bio-analysis applications. [0007] Furthermore, the silicon diaphragm has a very high Young's modulus of about 100 Gpa. A micro-pump having such a diaphragm generally has a low compression ratio, which is defined by: .epsilon.=(.DELTA.V+V.sub.0)/V.sub.0 [0008] where [0009] .DELTA.V is the stroke volume, and [0010] V.sub.0 is the dead volume, which is a volume of fluid that is not displaced in a pumping chamber during a pumping cycle. [0011] A low compression ratio is disadvantageous for a micro-pump where self-priming is concerned. To achieve self-priming in a micro-pump, i.e. to be able to pump as much gas and gas bubbles out of the micro-pump, the compression ratio needs to be maximized. To maximize compression ratio, the dead volume must be minimized while the stroke volume maximized. This maximizing of a stroke volume of a micro-pump having a silicon diaphragm is not easily achieved, especially if the micro-pump has a pumping chamber with angular profiles and/or the diaphragm is driven with an actuator, such as a piezo element that is capable of generating only a limited actuation force. Such a micro-pump may exhibit a relatively large dead volume due to a mismatch between the shapes of the silicon diaphragm and the pumping chamber. [0012] K. P. Kamper, J. Dopper, W. Ehrfeld, and S. Oberbeck, "A self-filling low-cost membrane micro-pump", The 11.sup.th annual international workshop on MEMS. 1998, Heidelberg Germany, pp. 432-43, discloses a micro-pump having a layered construction that has a relatively high compression ratio. This micro-pump includes top and bottom molded polycarbonate housing parts that include microstructures formed therein that serve as inlet and outlet valves and alignment structures. A polycarbonate valve membrane separates the top and bottom parts. The micro-pump also includes a pump membrane, which is separate from the valve membrane. The pump membrane is mounted on top of the upper housing part. Fluidic connection between a space underneath the pump membrane and a valve plane where the valve membrane is located is achieved by two cylindrical through-holes in the upper housing part. SUMMARY [0013] According to an embodiment of the invention, there is provided a micro-pump. The micro-pump includes a first layer, a second layer and a third intermediate flexible layer. The first layer includes an inlet recess, an inlet channel in fluid communication with the inlet recess and an outlet channel. The second layer includes an outlet and an inlet. The first layer and the second layer are disposed such that the inlet is opposite the inlet recess and at least a portion of the outlet channel is opposite the outlet. At least one of the first layer and the second layer includes a pumping chamber in fluid communication with the inlet channel and the outlet channel. The intermediate flexible layer includes an inlet slit and an outlet slit positioned therein. The intermediate flexible layer also includes an actuatable portion, a first valve portion adjacent the inlet slit and a second valve portion adjacent the outlet slit. The actuatable portion abuts the pumping chamber. The first valve portion is disposed over the inlet to block fluid passage between the inlet and the inlet recess. The first valve portion is moveable away from the inlet in response to a first actuation of the actuatable portion to allow the inlet to be in fluid communication with the inlet recess through the inlet slit. The second portion is disposed between the outlet channel and the outlet so as to block fluid passage between the outlet channel and the outlet. The second valve portion is moveable away from the outlet channel in response to a second actuation of the actuatable portion to allow the outlet channel to be in fluid communication with the outlet through the outlet slit. [0014] The pumping chamber may be defined by two respective pumping recesses in the first layer and the second layer. In such a case, the actuatable portion of the intermediate flexible layer is arranged between the pumping recesses. The inlet of the second layer may include a recess surrounding a pedestal, the pedestal being in abutment with the inlet slit of the intermediate flexible layer. The outlet channel of the first layer may include a recess surrounding a pedestal, the pedestal being in abutment with the outlet slit of the intermediate flexible layer. [0015] The structure of the first layer and the second layer, for the above-described embodiment, are largely identical and may therefore be molded using a single mold. Accordingly, the pump of the invention can be manufactured cost-effectively and by a relatively simple process. The features peculiar to the first layer and the second layer may then be formed in the respective layers after the layers are molded. [0016] The intermediate flexible layer may be made of any material that has a flexibility sufficient for actuation to ensure the transport of liquid through the pump. For example, it can be made out of a thin metal foil, of a thin film of a semiconductor, such as silicon, or of a polymeric material. A suitable intermediate layer is a membrane layer of a low Young's modulus. With such a layer, the actuatable portion of the intermediate flexible layer may be closely urged against the wall of the pumping chamber to increase the compression ratio of the micro-pump. The intermediate flexible layer may be at least substantially flat. Such a layer is easy to manufacture. BRIEF DESCRIPTION OF DRAWINGS [0017] The invention will be better understood with reference to the drawings, in which: [0018] FIG. 1 is an exploded isometric drawing of a micro-pump according to an embodiment of the invention, wherein the micro-pump includes a top layer, an intermediate layer and a bottom layer; [0019] FIG. 2 is an isometric drawing showing an undersurface of the top layer in FIG. 1; [0020] FIGS. 3A-3E are drawings showing plan views of an annular recess surrounding a pedestal on the undersurface of the top layer in FIG. 2, the annular recess and the pedestal are shown in different shapes; [0021] FIG. 4 is a sectioned drawing of a micro-pump similar to the micro-pump in FIG. 1, showing the top layer snap-fitted to the bottom layer; [0022] FIG. 5A is a sectioned drawing of the micro-pump in FIG. 1, taken along line |---| in FIG. 1, wherein the micro-pump is shown assembled and in a non-actuated state; Continue reading about Micro-pump... Full patent description for Micro-pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Micro-pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Micro-pump or other areas of interest. ### Previous Patent Application: Fan for generating air flow Next Patent Application: Discharge pressure actuated pump Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Micro-pump patent info. IP-related news and info Results in 0.16344 seconds Other interesting Feshpatents.com categories: Novartis , Pfizer , Philips , Polaroid , Procter & Gamble , 174 |
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